6.3: Lab 6 Assignment: Collection/Field Sampling - Biology

Name: __________________________________

Part I. Soil/Leaf Litter Samples

We are going to make use of the bank of Berlese funnels in the back of the classroom (finally!). As a class, we’re going to examine the soil arthropod communities in response to two dimensions: linear distance from edge habitat and soil depth.

  1. Linear Distance Samples

At our study site, we’ll begin at the immediate edge of a chosen habitat or disturbance and take our first edge-habitat sample. We will remove the upper 10 x 10 x 10 cm of soil/leaf litter. The second sample will be taken 10 meters from the selected start-point and the third will be 20 meters from the start-point. The samples will be of equal size. Each will be clearly labeled and brought back to the classroom.

  1. Soil Depth

At the FIRST linear distance sample location (0m), two additional samples will be taken of the next successive 10cm of soil each (depth = 20 cm, depth = 30cm). These will also be clearly labeled and returned to the classroom.

The class will be broken into groups responsible for each soil sample. Once you have collected and clearly labeled your soil sample, we will have time to collect for approximately 30 minutes before returning to the classroom to complete lab.

  1. What was your specific role in collecting soil samples for lab?
  1. What differences in arthropod communities would you expect to see along the linear transect?
  1. What differences would you expect to see in arthropod morphology with increasing soil depth?

Part II. Collection Review

Today, we’re using the Berlese funnels to survey for soil arthropods. Is this an active or passive collection technique?

Which collection method is the best for capturing insects with piercing/sucking mouthparts on ornamental trees and shrubs?

Which collection method is the best for nocturnal, ground-dwelling insect? Is this active or passive collection?

Using the Pocket Guide provided, give three ways to monitor a production system for the presence of natural enemies:

  1. ____________________________________________
  1. ____________________________________________
  1. ____________________________________________


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National Research Council (US) Committee on Prudent Practices in the Laboratory. Prudent Practices in the Laboratory: Handling and Management of Chemical Hazards: Updated Version. Washington (DC): National Academies Press (US) 2011.

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A small chemistry experiment in a college laboratory, for example, costs very little, and mistakes or validity problems easily rectified. At the other end of the scale, a medical experiment taking samples from thousands of people from across the world is expensive, often running into the millions of dollars.

Finding out that there was a problem with the equipment or with the statistics used is unacceptable, and there will be dire consequences.

A field research project in the Amazon Basin costs a lot of time and money, so finding out that the electronics used do not function in the humid and warm conditions is too late.

To test the feasibility, equipment and methods, researchers will often use a pilot study, a small-scale rehearsal of the larger research design. Generally, the pilot study technique specifically refers to a smaller scale version of the experiment, although equipment tests are an increasingly important part of this sub-group of experiments.

For example, the medical researchers may conduct a smaller survey upon a hundred people, to check that the protocols are fine.

The Amazon Researchers may perform an experiment, in similar conditions, sending a small team either to the Amazon to test the procedures, or by using something like the tropical bio-dome at the Eden Project.

Pilot studies are also excellent for training inexperienced researchers, allowing them to make mistakes without fear of losing their job or failing the assignment.

Logistical and financial estimates can be extrapolated from the pilot study, and the research question, and the project can be streamlined to reduce wastage of resources and time.

Pilots can be an important part of attracting grants for research as the results can be placed before the funding body.

Generally, most funding bodies see research as an investment, so are not going to dole out money unless they are certain that there is a chance of a financial return.

Unfortunately, there are seldom paper reporting the preliminary pilot study, especially if problems were reported, is often stigmatized and sidelined. This is unfair, and punishes researchers for being methodical, so these attitudes are under a period of re-evaluation.

Discouraging researchers from reporting methodological errors, as found in pilot studies, means that later researchers may make the same mistakes.

The other major problem is deciding whether the results from the pilot study can be included in the final results and analysis, a procedure that varies wildly between disciplines.

Pilots are rapidly becoming an essential pre-cursor to many research projects, especially when universities are constantly striving to reduce costs. Whilst there are weaknesses, they are extremely useful for driving procedures in an age increasingly dominated by technology, much of it untested under field conditions.


Field research has a long history. Cultural anthropologists have long used field research to study other cultures. Although the cultures do not have to be different, this has often been the case in the past with the study of so-called primitive cultures, and even in sociology the cultural differences have been ones of class. The work is done. in "'Fields' that is, circumscribed areas of study which have been the subject of social research". [1] Fields could be education, industrial settings, or Amazonian rain forests. Field research may be conducted by zoologists such as Jane Goodall. Radcliff-Brown [1910] and Malinowski [1922] were early cultural anthropologists who set the models for future work. [2]

Business use of Field research is an applied form of anthropology and is as likely to be advised by sociologists or statisticians in the case of surveys.

Consumer marketing field research is the primary marketing technique used by businesses to research their target market.

The quality of results obtained from field research depends on the data gathered in the field. The data in turn, depend upon the field worker, his or her level of involvement, and ability to see and visualize things that other individuals visiting the area of study may fail to notice. The more open researchers are to new ideas, concepts, and things which they may not have seen in their own culture, the better will be the absorption of those ideas. Better grasping of such material means a better understanding of the forces of culture operating in the area and the ways they modify the lives of the people under study. Social scientists (i.e. anthropologists, social psychologists, etc.) have always been taught to be free from ethnocentrism (i.e. the belief in the superiority of one's own ethnic group), when conducting any type of field research.

When humans themselves are the subject of study, protocols must be devised to reduce the risk of observer bias and the acquisition of too theoretical or idealized explanations of the workings of a culture. Participant observation, data collection, and survey research are examples of field research methods, in contrast to what is often called experimental or lab research.

When conducting field research, keeping an ethnographic record is essential to the process. Field notes are a key part of the ethnographic record. The process of field notes begin as the researcher participates in local scenes and experiences in order to make observations that will later be written up. The field researcher tries first to take mental notes of certain details in order that they be written down later.

Kinds of field notes Edit

Types of Field Notes Brief Description
Jot Notes Key words or phrases are written down while in the field.
Field Notes Proper A description of the physical context and the people involved, including their behavior and nonverbal communication.
Methodological Notes New ideas that the researcher has on how to carry out the research project.
Journals and Diaries These notes record the ethnographer's personal reactions, frustrations, and assessments of life and work in the field.

Another method of data collection is interviewing, specifically interviewing in the qualitative paradigm. Interviewing can be done in different formats, this all depends on individual researcher preferences, research purpose, and the research question asked.

In qualitative research, there are many ways of analyzing data gathered in the field. One of the two most common methods of data analysis are thematic analysis and narrative analysis. As mentioned before, the type of analysis a researcher decides to use depends on the research question asked, the researcher's field, and the researcher's personal method of choice.

Anthropology Edit

In anthropology, field research is organized so as to produce a kind of writing called ethnography. Ethnography can refer to both a methodology and a product of research, namely a monograph or book. Ethnography is a grounded, inductive method that heavily relies on participant-observation. Participant observation is a structured type of research strategy. It is a widely used methodology in many disciplines, particularly, cultural anthropology, but also sociology, communication studies, and social psychology. Its aim is to gain a close and intimate familiarity with a given group of individuals (such as a religious, occupational, or sub cultural group, or a particular community) and their practices through an intensive involvement with people in their natural environment, usually over an extended period of time. The method originated in field work of social anthropologists, especially the students of Franz Boas in the United States, and in the urban research of the Chicago School of sociology. [3]

Anthropological fieldwork uses an array of methods and approaches that include, but are not limited to: participant observation, structured and unstructured interviews, archival research, collecting demographic information from the community the anthropologist is studying, and data analysis. Traditional participant observation is usually undertaken over an extended period of time, ranging from several months to many years, and even generations. An extended research time period means that the researcher is able to obtain more detailed and accurate information about the individuals, community, and/or population under study. Observable details (like daily time allotment) and more hidden details (like taboo behavior) are more easily observed and interpreted over a longer period of time. A strength of observation and interaction over extended periods of time is that researchers can discover discrepancies between what participants say—and often believe—should happen (the formal system) and what actually does happen, or between different aspects of the formal system in contrast, a one-time survey of people's answers to a set of questions might be quite consistent, but is less likely to show conflicts between different aspects of the social system or between conscious representations and behavior.

Archaeology Edit

Field research lies at the heart of archaeological research. It may include the undertaking of broad area surveys (including aerial surveys) of more localised site surveys (including photographic, drawn, and geophysical surveys, and exercises such as fieldwalking) and of excavation.

Biology Edit

In biology, field research typically involves studying of free-living wild animals in which the subjects are observed in their natural habitat, without changing, harming, or materially altering the setting or behavior of the animals under study. Field research is an indispensable part of biological science.

Animal migration tracking (including bird ringing/banding) is a frequently-used field technique, allowing field scientists to track migration patterns and routes, and animal longevity in the wild. Knowledge about animal migrations is essential to accurately determining the size and location of protected areas.

Earth and atmospheric sciences Edit

In geology fieldwork is considered an essential part of training [4] and remains an important component of many research projects. In other disciplines of the Earth and atmospheric sciences, field research refers to field experiments (such as the VORTEX projects) utilizing in situ instruments. Permanent observation networks are also maintained for other uses but are not necessarily considered field research, nor are permanent remote sensing installations.

Economics Edit

The objective of field research in economics is to get beneath the surface, to contrast observed behaviour with the prevailing understanding of a process, and to relate language and description to behavior (e.g. Deirdre McCloskey, 1985).

The 2009 Nobel Prize Winners in Economics, Elinor Ostrom and Oliver Williamson, have advocated mixed methods and complex approaches in economics and hinted implicitly to the relevance of field research approaches in economics. [5] In a recent interview Oliver Williamson and Elinor Ostrom discuss the importance of examining institutional contexts when performing economic analyses. [6] Both Ostrom and Williamson agree that "top-down" panaceas or "cookie cutter" approaches to policy problems don't work. They believe that policymakers need to give local people a chance to shape the systems used to allocate resources and resolve disputes. Sometimes, Ostrom points out, local solutions can be the most efficient and effective options. This is a point of view that fits very well with anthropological research, which has for some time shown us the logic of local systems of knowledge — and the damage that can be done when "solutions" to problems are imposed from outside or above without adequate consultation. Elinor Ostrom, for example, combines field case studies and experimental lab work in her research. Using this combination, she contested longstanding assumptions about the possibility that groups of people could cooperate to solve common pool problems (as opposed to being regulated by the state or governed by the market. [7]

Edward J. Nell argued in 1998 that there are two types of field research in economics. One kind can give us a carefully drawn picture of institutions and practices, general in that it applies to all activities of a certain kind of particular society or social setting, but still specialized to that society or setting. Although institutions and practices are intangibles, such a picture will be objective, a matter of fact, independent of the state of mind of the particular agents reported on. Approaching the economy from a different angle, another kind of fieldwork can give us a picture of the state of mind of economic agents (their true motivations, their beliefs, state knowledge, expectations, their preferences and values). [8]

Public health Edit

In public health, the use of the term field research refers to epidemiology or the study of epidemics through the gathering of data about the epidemic (such as the pathogen and vector(s) as well as social or sexual contacts, depending upon the situation).

Management Edit

Mintzberg played a crucial role in the popularization of field research in management. The tremendous amount of work that Mintzberg put into the findings earned him the title of leader of a new school of management, the descriptive school, as opposed to the prescriptive and normative schools that preceded his work. The schools of thought derive from Taylor, Henri Fayol, Lyndall Urwick, Herbert A. Simon, and others endeavored to prescribe and expound norms to show what managers must or should do. With the arrival of Mintzberg, the question was no longer what must or should be done, but what a manager actually does during the day. More recently, in his 2004 book Managers Not MBAs, Mintzberg examined what he believes to be wrong with management education today.

Aktouf (2006, p. 198) summed-up Mintzberg observations about what takes place in the field:‘’First, the manager’s job is not ordered, continuous, and sequential, nor is it uniform or homogeneous. On the contrary, it is fragmented, irregular, choppy, extremely changeable and variable. This work is also marked by brevity: no sooner has a manager finished one activity than he or she is called up to jump to another, and this pattern continues nonstop. Second, the manager’s daily work is a not a series of self-initiated, willful actions transformed into decisions, after examining the circumstances. Rather, it is an unbroken series of reactions to all sorts of request that come from all around the manager, from both the internal and external environments. Third, the manager deals with the same issues several times, for short periods of time he or she is far from the traditional image of the individual who deals with one problem at a time, in a calm and orderly fashion. Fourth, the manager acts as a focal point, an interface, or an intersection between several series of actors in the organization: external and internal environments, collaborators, partners, superiors, subordinates, colleagues, and so forth. He or she must constantly ensure, achieve, or facilitate interactions between all these categories of actors to allow the firm to function smoothly.’’

Sociology Edit

Pierre Bourdieu played a crucial role in the popularization of fieldwork in sociology. During the Algerian War in 1958–1962, Bourdieu undertook ethnographic research into the clash through a study of the Kabyle people (a subgroup of the Berbers), which provided the groundwork for his anthropological reputation. His first book, Sociologie de L'Algerie (The Algerians), was an immediate success in France and was published in America in 1962. A follow-up, Algeria 1960: The Disenchantment of the World: The Sense of Honour: The Kabyle House or the World Reversed: Essays, published in English in 1979 by Cambridge University Press, established him as a major figure in the field of ethnology and a pioneer advocate scholar for more intensive fieldwork in social sciences. The book was based on his decade of work as a participant-observer with Algerian society. One of the outstanding qualities of his work has been his innovative combination of different methods and research strategies as well as his analytical skills in interpreting the obtained data.

Throughout his career, Bourdieu sought to connect his theoretical ideas with empirical research, grounded in everyday life. His work can be seen as sociology of culture. Bourdieu labeled it a "theory of practice". His contributions to sociology were both empirical and theoretical. His conceptual apparatus is based on three key terms, namely, habitus, capital and field. Furthermore, Bourdieu fiercely opposed rational choice theory as grounded in a misunderstanding of how social agents operate. Bourdieu argued that social agents do not continuously calculate according to explicit rational and economic criteria. According to Bourdieu, social agents operate according to an implicit practical logic—a practical sense—and bodily dispositions. Social agents act according to their "feel for the game" (the "feel" being, roughly, habitus, and the "game" being the field).

Bourdieu's anthropological work was focused on the analysis of the mechanisms of reproduction of social hierarchies. Bourdieu criticized the primacy given to the economic factors, and stressed that the capacity of social actors to actively impose and engage their cultural productions and symbolic systems plays an essential role in the reproduction of social structures of domination. Bourdieu's empirical work played a crucial role in the popularization of correspondence analysis and particularly multiple correspondence analysis. Bourdieu held that these geometric techniques of data analysis are, like his sociology, inherently relational. In the preface to his book The Craft of Sociology, Bourdieu argued that: "I use Correspondence Analysis very much, because I think that it is essentially a relational procedure whose philosophy fully expresses what in my view constitutes social reality. It is a procedure that 'thinks' in relations, as I try to do it with the concept of field."

One of the classic ethnographies in Sociology is the book Ain't No Makin' It: Aspirations & Attainment in a Low-Income Neighborhood by Jay MacLeod. [ citation needed ] The study addresses the reproduction of social inequality among low-income, male teenagers. The researcher spent time studying two groups of teenagers in a housing project in a Northeastern city of the United States. The study concludes that three different levels of analysis play their part in the reproduction of social inequality: the individual, the cultural, and the structural. [9]

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As the name suggests, a field study is an experiment performed outside the laboratory, in the 'real' world. Unlike case studies and observational studies, a field experiment still follows all of the steps of the scientific process, addressing research problems and generating hypotheses.

The obvious advantage of a field study is that it is practical and also allows experimentation, without artificially introducing confounding variables.

A population biologist examining an ecosystem could not move the entire environment into the laboratory, so field experiments are the only realistic research method in many fields of science.

In addition, they circumvent the accusation leveled at laboratory experiments of lacking external or ecological validity, or adversely affecting the behavior of the subject.

Social scientists and psychologists often used field experiments to perform blind studies, where the subject was not even aware that they were under scrutiny.

A good example of this is the Piliavin and Piliavin experiment, where the propensity of strangers to help blood covered 'victims' was measured. This is now frowned upon, under the policy of informed consent, and is only used in rare and highly regulated circumstances.

Field experiments can suffer from a lack of a discrete control group and often have many variables to try to eliminate.

For example, if the effects of a medicine are studied, and the subject is instructed not to drink alcohol, there is no guarantee that the subject followed the instructions, so field studies often sacrifice internal validity for external validity.

For fields like biology, geology and environmental science, this is not a problem, and the field experiment can be treated as a sound experimental practice, following the steps of the scientific method.

A major concern shared by all disciplines is the cost of field studies, as they tend to be very expensive.

For example, even a modestly sized research ship costs many thousands of dollars every day, so a long oceanographical research program can run into the millions of dollars.

Pilot studies are often used to test the feasibility of any long term or extensive research program before committing vast amounts of funds and resources. The changeable nature of the external environment and the often-prohibitive investment of time and money mean that field experiments are rarely replicable, so any generalization is always tenuous.

What do you like most about being a lab assistant?

The interviewer would like to know more about what aspects of this job you enjoy most. Answer from the heart and be sure to show your excitement for your career choice.

"The part that I enjoy most about being a laboratory assistant is the variety of knowledge that I gain in a day. There are always new medical terms to learn, and I am consistently feeling challenged."

"I am new to my career as a laboratory assistant however, I believe that the aspect I will most enjoy will be the variety of tasks and research in a day. I am an active learner and appreciate the opportunity you will give me to begin growing my career."

"I am new to this job position. Still, I believe that being a lab assistant can help me understand more what it is like to be in a lab setting, become more familiarized with the system, how labs are supposed to run and gain the hands-on experience of being part of the lab staff."

It sounds as though you have a clear idea of what you will learn in this role. Nice job.

"What I like the most about being a student lab assistant at my university's chemistry department is that the work that I do is fun. Even though this is not my final choice of career, I enjoy the work that I do, and I enjoy being able to learn. I hope that one day, the skills that I learn here will be useful in the lab in which I end up."

Your response is positive and shows a willingness to try a variety of career paths. I have reworked the grammar a touch to avoid run-on sentences.

"What I like the most about being a student lab assistant at my university's chemistry department is that the work that I do is fun. Even though this is not my final choice of career, I enjoy the work that I do, and I appreciate being able to learn continually. I believe the skills I have gained in this role will be useful, here."

Chapter 6. Working With Captured Packets

Once you have captured some packets or you have opened a previously saved capture file, you can view the packets that are displayed in the packet list pane by simply clicking on a packet in the packet list pane, which will bring up the selected packet in the tree view and byte view panes.

You can then expand any part of the tree to view detailed information about each protocol in each packet. Clicking on an item in the tree will highlight the corresponding bytes in the byte view. An example with a TCP packet selected is shown in Figure 6.1, “Wireshark with a TCP packet selected for viewing”. It also has the Acknowledgment number in the TCP header selected, which shows up in the byte view as the selected bytes.

Figure 6.1. Wireshark with a TCP packet selected for viewing

You can also select and view packets the same way while Wireshark is capturing if you selected “Update list of packets in real time” in the “Capture Preferences” dialog box.

In addition you can view individual packets in a separate window as shown in Figure 6.2, “Viewing a packet in a separate window”. You can do this by double-clicking on an item in the packet list or by selecting the packet in which you are interested in the packet list pane and selecting View → Show Packet in New Window . This allows you to easily compare two or more packets, even across multiple files.

Figure 6.2. Viewing a packet in a separate window

Along with double-clicking the packet list and using the main menu there are a number of other ways to open a new packet window:

Measuring Racial Discrimination (2004)

6 Experimental Methods for Assessing Discrimination

As we discussed in Chapter 5,at the core of assessing discrimination is a causal inference problem. When racial disparities in life outcomes occur, explicit or subtle prejudice leading to discriminatory behavior and processes is a possible cause, so that the outcomes could represent, at least in part, the effect of discrimination. Accurately determining what constitutes the effect of discrimination, personal choice, and other related and unrelated factors requires the ability to draw clear causal inferences. In this chapter, we review two experimental approaches that have been used by researchers to reach causal conclusions about racial discrimination: laboratory experiments and field experiments (particularly audit studies).


Experimental Design

To permit valid causal inferences about racial discrimination, the design of an experiment and the analytic method used in conjunction with that design must address several issues. First, there are frequently intervening or confounding variables that are not of direct interest but that may affect the outcome. The effects of these variables must be accounted for in the study design and analysis. In controlled laboratory experiments, the investigator manipulates a variable of interest, randomly assigns participants to different conditions of the variable or treatments, and measures their responses to the manipulation while attempting to control for other

relevant conditions or attributes. As described in the previous chapter, randomization greatly increases the likelihood of being able to infer that an observed difference between the treatment and control groups is causal. Observing a difference in outcome between the groups of participants can be the basis for a causal inference. In controlled field experiments, researchers analyze the results of a deliberately manipulated factor of interest, such as the race of an interviewer. They attempt to control carefully for any intervening or confounding variables. Random assignment of treatments to participants is frequently used to reduce any doubts about lingering effects of unobserved variables, provided, of course, that one can actually apply the randomization to the variable of interest.

In addition to the problem of credibly designing an experiment that supports a causal inference, a common weakness of experiments is a lack of external validity. That is, the results of the experiment may not generalize to individuals other than those enrolled in the experiment, or to different areas or populations with different economic or sociological environments, or to attributes that differ from those tested in the experiment.

Despite these problems, the strengths of experiments for answering some types of questions are undeniable. Even if their results may not be completely generalizable and even if they do not always capture all the relevant aspects of the issue of interest, experiments provide more credible evidence than other methods for measuring the effects of an attribute (e.g., race) in one location and on one population.

Using Experiments to Measure Racial Discrimination

Use of an experimental design to measure racial discrimination raises important questions because race cannot be directly manipulated or assigned randomly to participants. Researchers who use randomized controlled experiments to measure discrimination, therefore, can manipulate race by either varying the &ldquoapparent&rdquo race of a target person as the experimental treatment or can manipulate &ldquoapparent&rdquo discrimination by randomly assigning study participants to being treated with different degrees of discrimination.

In the first case, the experimenter varies the treatment, namely, the apparent race, by such means as by providing race-related cues on job applications (e.g., name or school attended) or by showing photographs to participants in which the only differences are skin color and facial features. The experimenter then measures whether participants respond differently under one race treatment compared with another (e.g., evaluating black versus white job applicants or associating positive or negative attributes with photographs of blacks versus whites). In such a study, the experimenter elicits responses from the participants to determine the effect of

apparent race on their behavior (e.g., whether the participants engage in discriminatory behavior toward black and not white applicants). That is, they measure the behavior of potential discriminators toward targets of different races. If successful, then finding a difference in behavior would indicate an effect of race.

In the second instance, experimenters randomly assign participants to be treated differently, that is, either with or without discrimination. This type of experiment attempts to measure the response to discrimination rather than directly measure the expression of discrimination&mdashthat is, it measures the behavior of potential targets of discrimination. Because race cannot be experimentally manipulated, an explicit specification of the behavioral process is needed that allows the translation of results from such experiments into causal statements about the actual discrimination mechanism measured in the experiment (i.e., the extent to which the experimenter can manipulate some other factor related to race, such as perception). To our knowledge, no one has attempted to carry out such formal reverse reasoning, and we believe that doing so is especially crucial when arguing for the external validity of experimental results.

One of the few examples of attempts to perform similar inferential reversals is the special case of understanding odds ratios (and adjusted odds ratios) in the context of comparing retrospective and prospective studies on categorical variables. In retrospective studies, the data are collected only after the treatment has taken place, whereas in prospective studies the data are collected on possible covariates before treatment and on outcomes after the treatment. If one has both categorical explanatory and categorical response variables, one can estimate their relationship in the prospective study based on a retrospective sample. If the logistic causal model is correct, the inference about the key causal coefficient from the retrospective study is the same as if one had done a prospective sampling on the explanatory variable. 1 Those results, however, do not generalize to relationships among continuous variables.



Laboratory experiments, like all experiments, include the standard features of (1) an independent variable that researchers can manipulate (i.e., assign conditions or treatments to participants) (2) random assignment to

Establishing that the logistic causal model is a valid representation of the process under study is very difficult, but it is clearly necessary to draw such conclusions.

treatment conditions and (3) control over extraneous variables that otherwise might be confounded with the independent variable of interest, potentially undermining the interpretation of causality. Laboratory experiments occur in a controlled setting, chosen for its ability to minimize confounding variables and other extraneous stimuli.

Laboratory experiments on discrimination would ideally measure reactions to the exact same person while manipulating only that person&rsquos race. As noted above, while strictly speaking one cannot manipulate the actual race of a single person, experimenters do typically either manipulate the apparent race of a target person or randomly assign subjects or study participants to the experimental condition while attempting to hold constant all other attributes of possible relevance. One common method of varying race is for experimenters to train several experimental confederates&mdashboth black and white&mdashto interact with study participants according to a prepared script, to dress in comparable style, and to represent comparable levels of baseline physical attractiveness (see, e.g., Cook and Pelfrey, 1985 Dovidio et al., 2002 Henderson-King and Nisbett, 1996 Stephan and Stephan, 1989). Another common method of varying race involves preparing written materials and either incidentally indicating race or attaching a photograph of a black or white person to the materials (e.g., Linville and Jones, 1980).

Effects of race occur in concert with other situational or personal factors, called moderator variables, that may increase or decrease the effect of race on the participants&rsquo responses. In addition to manipulating a person&rsquos apparent race, for example, investigators may manipulate the person&rsquos apparent success or failure, cooperation or competition, helpfulness, friendliness, dialect, or credentials (see, e.g., Cook and Pelfrey, 1985 Dovidio et al., 2002 Henderson-King and Nisbett, 1996 Linville and Jones, 1980 Stephan and Stephan, 1989). Even more often, experimenters will manipulate features of the situation expected to moderate levels of bias toward black and white targets examples involve anonymity, potential retaliation, norms, motivation, time pressure, and distraction (Crosby et al., 1980). Finally, the study participants frequently are black and white college students (e.g., Crosby et al., 1980 Correll et al., 2002 Judd et al., 1995).

Strengths of Laboratory Experiments

Laboratory experiments, if well designed and executed, can have high levels of internal validity for causal inference&mdashthat is, they are designed to measure exactly what causes what. The direction of causality follows from the manipulation of randomly assigned independent variables that control for two kinds of unwanted, extraneous effects: systematic (confounding) variables and random (noise) variables.

Laboratory experiments are the method of choice for isolating a single variable of interest, particularly when fine-tuned manipulation of precisely defined independent variables is required. Laboratory studies also allow precise measurement of dependent variables (such as response time or inches in seating distance). The laboratory setting gives experimenters a great degree of control over the attention of participants, potentially allowing them to maximize the impact of the manipulation in an otherwise bland environment.

Because of these fine-grained methods, laboratory experiments on discrimination are well suited to examining psychological processes. Both face-to-face interactions and processes in which single individuals react to racial stimuli are readily studied in such experiments. The most sophisticated experiments show not only the effect of some variable (e.g., expectancies) on an outcome variable (e.g., discriminatory behavior) but also the mechanism or process that mediates the effect (e.g., biased interpretations, nonverbal hostility, stereotypic associations). That is, when an experiment manipulates the apparent race of two otherwise equivalent job candidates or interaction partners (as in the interracial interaction studies described later in this chapter see Dovidio et al., 2002 Word et al., 1974), the experiment ideally should also measure some of the proposed explanatory psychological mechanisms (such as emotional prejudices and cognitive stereotypes, either implicit or explicit), as well as the predicted discrimination (either implicit behaviors, such as nonverbal reactions, or more explicit behaviors, such as verbal reactions).

A hallmark of the better laboratory experiments is that they not only test useful theories but also show how important, compelling phenomena (e.g., the automaticity of discrimination) can and do occur. Laboratory studies often show that very small, subtle alterations in a situation can have substantial effects on important outcome variables.

Measuring Racial Discrimination

Experimenters measure varying degrees of discrimination. Laboratory measures of discrimination begin with verbal hostility (e.g., in studies of interracial aggression), which can constitute discrimination, when, for example, negative personal comments result in a hostile work environment (see Chapter 3). At the next level are disparaging written ratings of an individual member of a particular group (Talaska et al., 2003). If unjustified, such negative evaluations can constitute discrimination in a school or workplace.

At the subtle behavioral level, laboratory studies measure nonverbal indicators of hostility, such as seating distance or tone of voice (Crosby et al., 1980). Related nonverbal measures include coding of overt facial ex-

pressions, as well as measurement of minute nonvisible movements in the facial muscles that constitute the precursors of a frown. Experimenters study these nonverbal behaviors because they, too, could result in a hostile environment.

Moving up a level, laboratory measures of discriminatory avoidance include participants&rsquo choice of whether to associate or work with a member of a racial outgroup, volunteer to help an organization, or provide direct aid to an outgroup member who requests it (Talaska et al., 2003). In a laboratory setting, segregation can be measured by how people constitute small groups or choose leaders in organizational teams (Levine and Moreland, 1998 Pfeffer, 1998). Finally, aggression against outgroups can be measured in laboratory settings by competitive games or teacher&ndashlearner scenarios in which one person is allowed to punish another&mdashan outgroup member&mdashwith low levels of shock, blasts of noise, or other aversive experiences (Crosby et al., 1980 Talaska et al., 2003).

A review of laboratory studies as of the early 1980s (Crosby et al., 1980) summarized the findings as follows. Experiments on unobtrusive forms of bias and prejudice showed that white bias was more prevalent than indicated by surveys. Experiments on helping, aggressive, and nonverbal behaviors indicated that (1) whites tended to help whites more often than they helped blacks, especially when they did not have to face the person in need of help directly (2) under sanctioned conditions (e.g., in competitive games or administration of punishment), whites acted aggressively against blacks more than against whites but only when the consequences to the aggressor were low (under conditions of no retaliation, no censure, and anonymity) and (3) white nonverbal behavior displayed a discrepancy between verbal nondiscrimination and nonverbal hostility or discomfort, betrayed in tone of voice, seating distance, and the like. This review sparked the realization, discussed in earlier chapters, that modern forms of discrimination can be subtle, covert, and possibly unconscious, representing a new challenge to careful measurement, both inside and outside the laboratory (survey measures for these forms of discrimination are discussed in Chapter 8).

Key Examples

Since the 1980s, laboratory experiments on discrimination have concentrated more on measuring subtle forms of bias and less on examining overt behaviors, such as helping others. This shift occurred precisely because of the discrepancy between some people&rsquos overtly egalitarian responses on surveys and their discriminatory responses when they think no one is looking, or at least when they have a nonprejudiced excuse for their discriminatory behavior. In Boxes 6-1 through 6-3, we describe three of the

BOX 6-1
A Classic Laboratory Experiment on Discrimination

In a pair of experiments, Word and colleagues (1974) elicited subtle nonverbal discriminatory behaviors from white interviewers against black job applicants and then demonstrated that such behaviors used against white applicants elicited behaviors stereotypically associated with blacks. The researchers first asked white college students to interview black and white high school applicants for a team that would plan a marketing campaign. Interviewers expected to see several applicants the first applicant always was white, followed by black and white applicants in a randomly counterbalanced order. Unbeknownst to the interviewer participants, the applicants were confederates of the experimenters, trained to respond in a standard way. Debriefing indicated that study participants were unaware of its purposes or that the alleged applicants were confederates (probably aided by the sequence including two white applicants and one black applicant). Extensive debriefing indicated no suspicion about the confederates.

The interviewers&rsquo nonverbal behavior indicated less immediacy (i.e., greater discomfort and less warmth) toward black than white applicants on a number of measures scored by judges behind one-way mirrors: greater physical seating distance, shorter interviews, and more speech errors. Although judges were not blind to the race of the confederates and therefore may have been influenced in their coding of the white interviewers&rsquo behavior, three points suggest that the researchers were able to

best examples of controlled laboratory experiments on discrimination, ranging from simpler classic to more recent sophisticated studies. In a classic example, Word et al. (1974) created working definitions of race and discrimination to investigate subtle yet potentially powerful effects of stereotypical expectations hypothesized to result in discrimination (see Box 6-1). Another famous experiment showed that researchers can study social perception processes hypothesized to underlie discrimination, in which people see what they want to see by interpreting ambiguous evidence to fit their stereotypical biases (Darley and Gross, 1983 see Box 6-2). And in a final experiment, Dovidio et al. (2002) showed that implicit forms of prejudice tended to lead to implicit but potentially important forms of discrimination, whereas explicit forms of prejudice tended to lead to explicit forms of discrimination (see Box 6-3).

obtain fairly unbiased coding: (1) the coding consisted largely of physical measurement (e.g., seating distance, number of minutes) and counting (e.g., number of speech errors) (2) judges were unaware of the study&rsquos hypotheses and (3) replications of the coded behaviors produced the expected results in a second study.

In the second experiment, white interviewers were confederates trained to behave nonverbally in either a more or less immediate way toward naive white applicants that is, they were trained to treat some of the white applicants as the black applicants in the previous study had been treated. White applicants treated as if they were black reciprocated with greater seating distance and more speech errors. They perceived the interviewer to be less friendly and less adequate. They also performed worse in the interview were judged less adequate for the job and appeared less calm, composed, and relaxed.

The overall point of this pair of experiments&mdashthe basic methods of which have since been replicated repeatedly&mdashis that researchers can investigate how simulating discrimination against whites can bring about the very behaviors that are stereotypically associated with blacks (or another disadvantaged racial group), and they can measure the hypothesized mechanisms involved&mdashthat is, subtle nonverbal cues unlikely to be analyzed consciously by either perceiver or target. Moreover, researchers can mimic the employment interview context to examine the potentially large effects that nonverbal forms of discrimination are hypothesized to have on people&rsquos ability to obtain a job.

Other provocative recent experiments have shown that actual discriminatory behavior can follow from subliminal exposure to racial and other demographic stimuli (Bargh et al., 1996). This work has revealed that exposure to concepts and stereotypes at speeds too fast for conscious recognition primes relevant behavior, even though participants cannot remember or report having seen the priming stimuli. For example, researchers randomly assigned participants to see, at subliminal speeds, words related to rudeness or neutral topics and showed that those participants exposed to rude words responded more rudely to an experimenter. In a parallel experiment, subliminal exposure to photographs of unfamiliar black male faces, as compared with white ones, was followed by more rude, hostile behavior when the white experimenter subsequently made an annoying request. Similar results have been demonstrated for exposure to phenomena related to being

BOX 6-2
Perceptions of Academic Performance

In a laboratory experiment conducted by Darley and Gross (1983), participants viewed a child depicted in a 6-minute videotape as coming from either a high or low socioeconomic background, based on the setting in which she was shown playing. When asked to rate her academic performance, they acknowledged not having enough information and rated her ability at grade level. Other participants saw the initial 6-minute videotape depicting socioeconomic status but also saw an additional 12-minute videotape that depicted the child taking an oral test on which her performance was mixed. Participants shown the second video after the first no longer demurred regarding the child&rsquos academic performance. Instead, they rated her performance as well below grade level if they had viewed the 6-minute video depicting low socioeconomic status and at grade level if they had seen the video depicting high socioeconomic status. Control participants shown the test video alone, and not also the socioeconomic status video, rated the child&rsquos performance at about grade level.

Thus, the researchers were able to show how people perceived the academic performance tape (itself quite neutral) through the lens of their expectations, convincing themselves that they had evidence on which to base their biased judgments. Although the child on the tape was white, the applicability of this sort of socioeconomic status-based stereotype to racially tainted judgments of academic performance appears clear, and manipulating such variables sheds light on hypothesized processes of discrimination. Methods for assessing this kind of perceptual confirmation process have been replicated repeatedly. For example, in a study conducted by Sagar and Schofield (1980), black and white sixth-grade boys viewed depictions of various ambiguously aggressive behaviors by black and white actors. Participants read identical verbal descriptions of four ambiguously aggressive incidents common in middle schools: bumping in the hallway, requesting another student&rsquos food, poking in the classroom, and using another&rsquos pencil without permission. The race of actors and targets was not specified verbally, but each incident was accompanied by one of four drawings of the event, identical except for the depicted race of the actor and target. Participants saw each incident only once and each in just one of the four possible combinations of actor race and target race. Participants rated how mean, threatening, friendly, and playful each incident was. Researchers were able to show that all the participants, regardless of race, rated the behaviors as more mean and threatening when a black child enacted them than when a white child did.

elderly, which resulted in participants walking more slowly to the elevator after the experiment. The point is that researchers can manipulate racial cues without participants&rsquo conscious awareness and measure subtle forms of behavior that, if occurring selectively toward members of one racial group or another, could constitute a hostile environment form of discrimination. Other more direct forms of discrimination are also possible to measure in such experiments, such as making negative comments in a job interview.

These examples illustrate the range of aspects of racial discrimination that can be examined in laboratory settings. Such experiments can manipulate racial and moderator variables test various hypothesized mechanisms of discrimination, such as attitudes and assess various hypothesized manifestations of discrimination, including verbal, nonverbal, and affiliative responses. They can also simulate pieces of real-world situations of interest, such as job applications and others. Most of the phenomena studied in experiments on race discrimination have been replicated in studies of gender discrimination and sometimes age, disability, class, or other ingroup&ndashoutgroup variations. Research indicates that gender, race, and age are the most salient, immediately encoded social categories (Fiske, 1998).

Limitations of Laboratory Experiments

Laboratory experiments usually are limited in time and measurement, so they generally do not aim to answer questions about behavior over long periods of time or behavior related to entire batteries of measures. The purpose of a laboratory experiment may include one or more of the following: (1) to demonstrate that an effect indeed can occur, at least under some conditions, with some people, for some period of time (2) to create a simulation or microcosm that includes the most important factors (3) to create a realistic psychological situation that is intrinsically compelling or (4) to test a theory that has obvious larger importance.

Laboratory experiments are also at risk for various biases related to the settings in which they occur. For example, they may be set up in such a narrow, constraining way that the participants have no choice but to respond as the experimenters expect (Orne, 1962). Crafting more subtle manipulations and providing true choice in response options can sometimes be used to limit the potential biases in such cases. In addition, the experimenter may inadvertently bias presentation of the manipulations and measures, so that participants are equally inadvertently induced to confirm the hypotheses (Rosenthal, 1976). This problem can often be addressed using double-blind methods, in which experimenters as well as participants are not aware of the treatment assigned to them. Participants may also worry

BOX 6-3
The Effect of Psychological Mechanisms on Measures of Discriminating Behavior

Laboratory experiments can create working definitions of manipulated race, randomly assign participants to interact with black or white confederates, and measure a variety of proposed psychological mechanisms (implicit and explicit attitudes) to determine their effect on various types of discriminatory behavior. For example, Dovidio et al. (2002) conducted a multiphase experiment on how whites&rsquo explicit and implicit racial attitudes predict bias and perceptions of bias in interracial interactions. At the beginning of the term, white college students completed a 20-item standardized measure of prejudice, the Attitudes Toward Blacks Scale. Later in the semester, 40 students (15 male and 25 female) participated in what they believed to be two separate studies. In the first, a decision task required participants to respond as quickly as possible&mdashafter the letter P or H was displayed on a computer screen&mdashas to whether a given word displayed for each trial could ever describe a person or a house. Unbeknownst to them, on critical trials versus practice trials the letter P was preceded by a standardized schematic sketch of a black or white man or woman, presented at subliminal speeds (0.250 seconds). This level of presentation has been shown repeatedly to prime relevant associations in memory and, in particular, stereotypes. As in countless other studies (e.g., see Fazio and Olson, 2003), the findings in this study revealed subtle forms of stereotypic association when people responded more quickly to negative words (&ldquobad,&rdquo &ldquocruel,&rdquo &ldquountrustworthy&rdquo) preceded by a black face and to positive words (&ldquogood,&rdquo &ldquokind,&rdquo &ldquotrustworthy&rdquo) preceded by a white face, and more slowly to the converse combinations. As is typical with this method, no participant reported being aware of the subliminal faces. Such studies show how researchers can measure automatic and unconscious racial bias, regardless of expressed levels of prejudice (Devine, 1989). At this point, then, the experimenters had access to two kinds of attitudes&mdashthe explicit ones expressed on the questionnaire and the implicit ones suggested by the participants&rsquo speed of stereotypic associations. These are the psychological causes of different kinds of discrimination hypothesized in the next step.

In what participants assumed to be a separate study focused on acquaintance processes, the participants met separately with two inter-

action partners&mdashone white and one black&mdashfor a 3-minute conversation about dating in the current era. Five white and four black student confederates, trained to behave comparably to each other, played the role of interaction partners. All were unaware of the study&rsquos hypotheses and the participants&rsquo levels of implicit and explicit prejudice. After each interaction, both the participant and the confederate (in separate rooms) completed scales assessing their own and each other&rsquos perceived friendliness (pleasant and not cold, unfriendly, unlikable, or cruel). Two coders used the same scales to rate, separately, participants&rsquo verbal and nonverbal behavior, respectively, from audiotapes and from videotapes on which only the participant was visible. Two more coders rated participants&rsquo overall friendliness from audio and video information combined. Analyses compared the differences in the participants&rsquo responses to the white and black confederates as rated by the participants themselves, the confederates, and the observers.

Two patterns of response emerged: one an explicit and overt sequence of processes, and the other an implicit and subtle sequence of processes. The explicit sequence involved overt measures of verbal behavior. White participants&rsquo scores on the attitudes questionnaire and their self-reported friendliness (both measures of explicit, overt prejudice) correlated with each other that is, whites&rsquo self-reported attitudes predicted bias in verbal friendliness toward black relative to white confederates. These measures also correlated with verbal friendliness as rated by observers from audiotapes (a measure of explicit, overt discriminatory behavior).

In contrast, the implicit sequence of processes was indicated by responses to subliminal primes (an implicit, subtle measure of prejudice), which correlated significantly with a series of implicit, subtle forms of discriminatory behavior: nonverbal behavior rated by observers from silent videotapes, confederate perceptions of participants&rsquo friendliness, and overall friendliness rated by other observers, which also correlated significantly with each other. In other words, whites&rsquo implicit attitudes predicted their bias and others&rsquo perceptions of bias in nonverbal friendliness. None of the explicit and implicit measures correlated significantly with each other, indicating that the implicit and explicit sequences are independent. Each sequence is important: Effect sizes were moderate to large by social science standards.

about whether their behavior is socially acceptable (Marlow and Crowne, 1961) and fail to react spontaneously. Nonreactive, unobtrusive, disguised measurement can avert this problem. It is worth noting that not all of these issues are unique to the laboratory. Many of the potential biases and artifacts of laboratory experiments also occur at least as often in other kinds of experiments (e.g., field experiments, which we turn to next), as well as with nonexperimental methods (natural experiments and observational studies, such as surveys).

Translating Experimental Effects

Laboratory experiments are useful for measuring psychological mechanisms that lead to discriminatory behavior (e.g., implicit or explicit stereotypes), but they do not describe the frequency of occurrence of such behavior in the world. They cannot, by their nature, say how often or how much a particular phenomenon occurs, such as what proportion of a racial disparity is a function of discriminatory behavior. Thus, they can be legitimately criticized on the grounds of low external validity&mdashthat is, limited generalizability to other samples, other settings, and other measures. Laboratory experimenters can sometimes make a plausible case for generalizability by varying plausible factors that might limit the applicability of the experiment. For example, if there are theoretically or practically compelling reasons for suspecting that an effect is limited to college sophomores, one might also replicate the study with business executives on campus for a seminar or retirees passing through for an Airstream conference. But laboratory experiments rarely randomly sample participants from the population of interest. Thus by themselves they cannot address external validity, and it is an empirical question whether or how well their findings translate into discrimination occurring in the larger population. In well-designed and well-executed experiments, the effects of confounding variables are randomized, allowing researchers to dismiss competing explanations as unlikely, but they are not entirely eliminated. For this reason, replication is important. In the study of discrimination, there are many laboratory experiment results that do not generalize in field settings. Findings either may diminish or not hold up over time. However, many other effects tested both in the laboratory and in the field have been consistent, some showing even stronger effects in the field (Brewer and Brown, 1998 Crosby et al., 1980 Johnson and Stafford, 1998).



Field experiments have many of the standard features commonly found in laboratory experiments. The term field experiment refers to any fully randomized research design in which people or other observational units found in a natural setting are assigned to treatment and control conditions. The typical field experiment uses a two-group, post-test-only control group design (Campbell and Stanley, 1963). In such a design, people are randomly assigned to treatment and control groups. An experimental manipulation is administered to the treatment group, and an outcome measure is obtained for both treatment and control groups. Because of random assignment, differences between the two groups provide some evidence of an effect of the manipulation. However, because no preexperiment measure for the outcome is obtained (which is an option in laboratory experiments), one cannot be altogether sure whether the groups are similar prior to the experiment. Nonetheless, randomization protects against this problem because it ensures that, on average, the two groups are similar except for the treatment.

Field experiments are attractive and often persuasive because, when done well, they can eliminate many of the obstacles to valid statistical inference. They can measure the impact of differential treatment more cleanly than nonexperimental approaches, yet they have the advantage of occurring in a realistic setting and hence are more directly generalizable than laboratory experiments. Furthermore, for measuring discrimination, they appear to reflect the broader public vision of what discrimination means&mdashthe treatment of two (nearly) identical people differently.

The social scientific knowledge necessary to design effective field experiments is stronger in some areas than in others. For example, our knowledge of the mechanisms and incentives underlying real estate markets is arguably more advanced than our knowledge of the incentives underlying labor markets (Yinger, 1995). Hence, our ability to use field experiments is correspondingly stronger for measuring behavior in housing markets than in other areas. We therefore focus our discussion below on a common methodology&mdashaudit or paired testing&mdashused particularly to assess discrimination in housing markets as well as in other areas. With the exception of a study we describe later (in Box 6-5), we do not review other types of field experiments in the domain of racial discrimination.

Audit or Paired-Testing Methodology 2 , 3

Audit or paired-testing methodology is commonly used to measure the level or frequency of discrimination in particular markets, usually in the labor market or in housing (Ross, 2002 for a summary of paired-testing studies in the labor and housing markets, see Bendick et al., 1994 Fix et al., 1993 Neumark, 1996 Riach and Rich, 2002). Auditors or testers are randomly assigned to pairs (one of each race) and matched on equivalent characteristics (e.g., socioeconomic status), credentials (e.g., education), tastes, and market needs. Members of each pair are typically trained to act in a similar fashion and are equipped with identical supporting documents. To avoid research subjects becoming suspicious when they confront duplicate sets of supporting documents, researchers sometimes vary the documents while keeping them similar enough that the two testers have equivalent levels of support.

As part of the study, testers are sent sequentially to a series of relevant locations to obtain goods or services or to apply for employment, housing, or college admission (Dion, 2001 Esmail and Everington, 1993 Fix et al., 1993 National Research Council, 1989 Schuman et al., 1983 Turner et al., 1991a, 1991b Yinger, 1995). The order of arrival at the location is randomly assigned. For example, in a study of hiring, testers have identical résumés and apply for jobs, whereas in a study of rental housing, they have identical rental histories and apply for housing. Once the study has been completed, researchers use the differences in treatment experienced by the testers as an estimate of discrimination.

To the extent that testers are matched on a relevant set of nonracial characteristics, systematic differences by the race of the testers can be used to measure discrimination on the basis of race. Propensity score matching is sometimes used when there are too many relevant characteristics on which to match on every one. In propensity score matching, an index of similarity is created by fitting a logistic regression with the outcome variable being race and the explanatory variables being the relevant characteristics on which one wishes to match. Subjects of one race are then paired or matched with subjects of the other race having similar fitted logit values&mdashthe pro-

In the following discussion on audit studies, we draw heavily on a commissioned paper by Ross and Yinger (2002) examining the challenges involved in measuring discrimination for both scholars and enforcement officials.

The term audit is used in a research context to refer to direct evidence of discrimination in a particular market (see Fix et al., 1993, for an overview of auditing). The term paired testing is used to refer to studies of discrimination conducted in an enforcement context to monitor civil rights compliance. Matching or pairing is also used more generally to refer to the widely used statistical method of comparing outcomes from individuals or groups of individuals that are similar in attributes other than the one of interest (e.g., race).

pensity score index (see Rosenbaum, 2002, and the references therein for a more complete description).

Paired-testing studies use an experimental design in natural settings to obtain information on apparently real outcomes and to assess the occurrence and prevalence of discrimination. An advantage to using paired tests is that individuals are matched on observed characteristics relevant to a particular market. Effective matching decreases the likelihood that differences are due to chance rather than discrimination because many factors are controlled for.

Paired testing is used in audit studies, such as the U.S. Department of Housing and Urban Development&rsquos (HUD&rsquos) national study of housing discrimination, to estimate overall levels of discrimination against racial and ethnic minorities. Audit studies can be highly effective enforcement tools for assessing treatment or detecting unfavorable treatment of members of disadvantaged groups (see Ross and Yinger, 2002). 4 Studies in the housing market (e.g., Wienk et al., 1979 Yinger, 1995) and in the labor market (e.g., Bendick et al., 1994 Cross et al., 1990 Neumark, 1996 Turner et al., 1991b) using the paired-testing methodology provide evidence of discrimination against racial minorities (see National Research Council, 2002b Ross and Yinger, 2002). In the case of housing, these studies might involve selecting a random sample of newspaper advertisements and then investigating the behavior of real estate agencies associated with these advertisements (Ross and Yinger, 2002). Employment audits are similarly based on a random sample of advertised jobs. While providing the generality valued by researchers, these studies also make it possible to observe the behavior of individual agencies or firms. This approach has been applied to other areas as well (see the examples in the next section).

Key Examples

Much of the use of audit or paired-testing methodology to study discrimination flows primarily from federal investigations concerning housing discrimination. National results of the 2000 Housing Discrimination Study (2000 HDS), conducted by the Urban Institute for HUD, show that housing discrimination persists, although its incidence has declined since 1989 for African Americans and Hispanics. Non-Hispanic whites are consistently favored over African Americans and Hispanics in metropolitan rental and

Ross and Yinger (2002) posit that because only a single audit is typically conducted for a given firm, audit studies can pose challenges for enforcement officials. One solution is to combine results from an audit study based on a random sample with results from audits of additional firms found to discriminate, thereby reducing the enforcement burden on targets of discrimination who file specific complaints.

sales markets (Turner et al., 2002b) similarly, Asians and Pacific Islanders in metropolitan areas nationwide (particularly homebuyers) face significant levels of discrimination (Turner et al., 2003 see Box 6-4 for a brief history of housing audits). In another example, Yinger (1986) studied the Boston housing rental and sales markets in 1981. In the rental market, whites discussed 17 percent more units with a rental agent and were invited to inspect 57 percent more units than blacks. In the sales market, whites discussed 35 percent more houses and were invited to inspect 34 percent more houses moreover, the difference in treatment was larger for low-income families and families with children. Yinger also found substantial variation in treat-

BOX 6-4
Housing Audits

Perhaps the most common method of assessing discrimination in housing is the fair housing audit. This approach, also referred to as paired testing in an enforcement context, is used in fair housing enforcement by private fair housing groups, public fair housing agencies, and the U.S. Department of Justice (Yinger, 1995). HUD has conducted several times what is by far the largest field experiment using matched-pair methodology&mdashthe Housing Discrimination Study (HDS). Results of the most recent 2000 HDS (released in November 2001) show that housing discrimination has declined since 1989 for African Americans and Hispanics, but it nonetheless persists: Non-Hispanic whites are consistently favored over African Americans and Hispanics in metropolitan rental and sales markets (Turner et al., 2002b). Similarly, Asians and Pacific Islanders in metropolitan areas nationwide (particularly homebuyers) face significant levels of discrimination (Turner et al., 2003 also, see National Research Council, 2002b, for a review of the 2000 HDS design).

Housing audits conducted after the passage of the Fair Housing Act (Title VIII of the Civil Rights Act of 1968) have been used to address discrimination and ensure equal opportunity in housing. The first audits were carried out by local fair housing organizations, often for purposes of enforcement but also to gather information. Results of the earliest audits were impaired by small sample sizes, nonrandom assignment methods, and failure to use standardized instruments and procedures. However, practices and methods gradually improved, and the cumulative body of work consistently showed that African Americans continued to suffer from various forms of housing discrimination despite the legal prohibition of such discrimination (see Galster, 1990a, 1990b, for reviews of local studies).

ment across neighborhoods. Taken together, these results document significant discrimination in the housing market.

As reported by Ross and Yinger (2002) and by Riach and Rich (2002), although the typical audit study concerns housing (e.g., Donnerstein et al., 1975 Schafer, 1979 Wienk et al., 1979 Yinger 1986), researchers have used variants of the design described above to examine discrimination in other areas. Areas studied include the labor market (Turner et al., 1991b), entry-level hiring (Cross et al., 1990), automobile purchases (e.g., Ayres and Siegelman, 1995), helping behaviors (Benson et al., 1976), small favors (Gaertner and Bickman, 1971), being reported for shoplifting (Dertke et al.,

The first attempt to measure housing discrimination nationally was carried out by HUD in the HDS of 1977. This study covered 40 metropolitan areas chosen to represent areas with central cities that were at least 11 percent black. The study confirmed the results of earlier local housing audits and demonstrated that discrimination was not confined to a few isolated cases (Wienk et al., 1979).

The 1977 HDS was replicated in 1988. Twenty audit sites were randomly selected from metropolitan areas having central-city populations exceeding 100,000 and that were more than 12 percent black. Real estate ads in major metropolitan newspapers were randomly sampled, and realtors were approached by auditors who inquired about the availability of the advertised unit and other units that might be on the market. The study covered both housing rentals and sales, and the auditors were assigned incomes and family characteristics appropriate to the housing unit advertised (Turner et al., 1991a).

The resulting data offered little evidence that discrimination against blacks had declined since the 1977 assessment (Yinger, 1993). The incidence of discriminatory treatment (defined as the percentage of encounters in which discrimination occurred) was over 50 percent in both the rental and the sales markets. The severity of the discrimination was also very high (severity being the number of units made available to whites but not blacks). Across indicators (e.g., number of advertised units shown, number of other units mentioned or shown, and location of units shown), between 60 and 90 percent of the housing units made available to whites were not brought to the attention of blacks. Over the course of the 1990s, various researchers carried out housing audits in different metropolitan areas using various methods (Galster, 1998 Massey and Lundy, 2001 Ondrich et al., 2000).

1974), obtaining a taxicab (Ridley et al., 1989), preapplication behavior by lenders (Smith and Delair, 1999 Turner et al., 2002a), and home insurance (Squires and Velez, 1988 Wissoker et al., 1997).

In an example involving automobile purchases, Ayres and Siegelman (1995) sent 38 testers (19 pairs) to 153 randomly selected Chicago-area new-car dealers to bargain over nine car models. Testers bargained for the same model (a model of their mutual choice) at the same location within a few days of each other. In contrast with the common paired-testing design, pair membership was not limited to a single pair instead, testers were assigned to multiple pairs. Also, testers did not know that the study was intended to investigate discrimination or that another tester would be sent to the same dealership. Testers were randomly allocated to dealerships, and the order of their visits was also randomly assigned. The testers were trained to follow a bargaining script in which they informed the dealer early on that they would not need financing. They followed two different bargaining strategies: one that depended on the behavior of the seller and another that was independent of seller behavior.

Ayres and Siegelman found that initial offers to white males were approximately $1,000 over dealer cost, whereas initial offers to black males were approximately $1,935 over dealer cost. White and black females received initial offers that were $1,110 and $1,320 above dealer cost, respectively. Final offers were lower, as expected, but the gaps remained largely unchanged. Compared with white males, black males were asked to pay $1,100 more to purchase a car, black females were asked to pay $410 more, and white females were asked to pay $92 more. These examples of evidence gleaned on market discrimination show the value of paired-testing methods for studying discrimination.

In Box 6-5, we provide an example of a field experiment on job hiring (Bertrand and Mullainathan, 2002) that emulates some of the best features of laboratory and audit studies. This study uses a large sample and avoids many of the problems of audit studies (e.g., auditor heterogeneity) by randomly assigning race to different résumés. It is a particularly good example of the possibilities of field study methodology to investigate racial discrimination.

Limitations of Audit Studies

Ross and Yinger (2002) discuss two main issues raised by researchers concerning the use of paired-testing methodology. They are (1) the accuracy of audit evidence and (2) its validity, particularly with respect to the target population. It is also worth noting that such studies typically require extensive effort to prepare and implement. They can be very expensive.

The Accuracy Issue

Many claim that the designs of audit studies are not true between-subjects experiments because research subjects (e.g., employer or housing agent) are not assigned to treatment or control groups but are exposed to both treatment and control (see Chapter 7 for a discussion of issues in repeated-measures designs). Also, although the order of exposure for each subject is randomized so that it should balance out, the time lapse between exposures makes it possible for the difference to be unrelated to the concept of focus (i.e., discrimination). In the time between two visits to an establishment, for example, someone else other than a tester may take the job or apartment of interest.

In the housing market, newspaper advertisements are used as a sampling frame (National Research Council, 2002b), but they may not accurately represent the sample of houses that are available or affordable to members of disadvantaged racial groups. Newspaper advertisements can be limiting because the sampling frame is restricted to members of disadvantaged racial groups who respond to typical advertisements and are qualified for the advertised housing unit or job. This limited sample may lead to a very specific interpretation of discrimination. For example, members of the sample may not be aware of alternative search strategies or know of other available housing units or jobs of interest. The practical difficulties associated with any sampling frame other than newspaper advertisements (and the associated steps of training auditors and assigning characteristics to them) are difficult to overcome.

The Validity Issue

Inferential target: estimating an effect of discrimination. Researchers have also debated the validity of audit studies (see the discussion in Ross and Yinger, 2002). Heckman and colleagues criticize the calculation of measures of discrimination (Heckman, 1998 Heckman and Siegelman, 1993). They argue that an estimate of discrimination at a randomly selected firm (or in an advertisement) does not measure the impact of discrimination in a market. Rather, discrimination should be measured by looking at (1) the average difference in the treatment of disadvantaged racial groups and whites or (2) the actual experience of the average member of a disadvantaged racial group, as opposed to examining the average experience of members of disadvantaged racial groups in a random sample of firms (i.e., the focus should be on the average across the population of applicants rather than the population of firms). Both of these proposed approaches to measuring discrimination are valid, but each has limitations.

Researchers typically determine the incidence of discrimination by mea-

BOX 6-5
Combining Features of Laboratory and Audit Studies

Bertrand and Mullainathan (2002) conducted a large-scale field experiment on job hiring by sending résumés in response to over 1,300 help-wanted advertisements in Boston and Chicago newspapers (submitting four résumés per ad). In all they submitted 4,890 résumés. For each city, the authors took résumés of actual job seekers, made them anonymous, and divided them into two pools based on job qualifications&mdashhigh and low. Two résumés from each pool were assigned to each advertisement, and race was randomly assigned within each pair. Thus, they randomly assigned white-sounding names (e.g., Allison and Brad) to two of the résumés and black-sounding names (e.g., Ebony and Darnell) to the remaining two résumés. This crucial randomization step breaks the tie between the résumé characteristics and race. Addresses were also randomized across résumés so that the ties between race and neighborhood characteristics and résumé attributes and neighborhood characteristics were also broken. Thus for each ad the researchers were able to observe differential callbacks by race both within and between the high- and low-qualified résumé pools.

Using callback rate as the outcome of interest, the authors found that on average, applicants with white-sounding names received 50 percent more callbacks than applicants with black-sounding names. Specifically, the researchers found a 12 percent callback rate for interviews for &ldquowhite&rdquo applicants compared with a 7 percent callback rate for interviews for &ldquoblack&rdquo applicants. They also found that higher-quality résumés yielded significant returns for white applicants (14 percent callback rate for white applicant/high-quality résumés versus 10 percent for white applicant/low-quality résumés) but not for black applicants (7.7 percent callback rate for black applicant/high-quality résumés versus 7.0 percent for black applicant/low-quality résumés). The authors concluded that for blacks having more productive skills may not necessarily reduce discrimination.

By randomizing the assignment of race, the authors made it possible to directly estimate the usual missing counterfactual&mdashwhether a callback would have been received if the résumé had belonged to an applicant likely to be perceived as being of the other race. Two résumés were selected from each pool (high- and low-qualified) because the same résumé could not be sent in response to a single advertisement with different names and addresses attached but otherwise identical content. Because race was randomized within each quality pair, any difference by race in the résumé quality (within a quality pool) for a particular advertisement could be expected to average out over a large number of advertisements. Thus the outcomes of the two résumés within a quality level could be compared, and the average of these comparisons could provide an estimate of the effect of race on callbacks within each quality level, which

would also provide an estimate of the effect of any interaction between race and qualifications.

More formally, with the analysis done at the résumé level, the causal effect of interest is as follows, where CB stands for callback, W for white, and B for black:

Because race was randomized within quality levels, which were assigned to particular advertisements within particular cities, this causal difference by race can be estimated within each of those categories by calculating

In addition, estimates for subpopulations within a quality level or city or type of advertisement can be estimated by summing just over those subpopulations.

These observations about the design and estimand of interest, along with the assumption of unit treatment additivity for city, advertisement, and a quality-by-race interaction effect, suggest the following model:

where f(.) is a function that produces a probability of callback. The outcome is measured with errors &epsilonijkl that are correlated within an advertisement, as they would be for observations within a cluster in a sample. Alternatively, the advertisements themselves can be included in the model, which makes the error terms independent. This model would take the form

where the extra subscript on the Ad variable acknowledges the fact that advertisements are nested within a city.

This design has several advantages over audit studies. One advantage is the ability to use a large number of résumés, as opposed to a smaller number of auditors, and thus the ability to send those résumés out to a large number of employers. The most significant advantage of this design is the ability of the researchers to randomize race, or a proxy for race, instead of trying to match actual people on as many characteristics as possible. The significant constraint this strategy imposes is that the outcome measured&mdashreceiving a callback from an employer&mdashis from the early stages of the job search, as is necessary when the only contact is a résumé.

One concern regarding this study is that there may be real or perceived characteristics, such as class, that are associated with distinctively African American or distinctively white names that differ from the real or perceived characteristics of these groups more generally. The authors checked whether differences in mothers&rsquo educational status by particular distinctive names correlated with differences in callback rates for particular names and found no significant correlation. However, this check does not address the present concern rather, it suggests that the researchers have the data to determine whether the educational status of mothers who give their children distinctively African American names differs from that of both African American and white mothers who do not give such names. The authors also report having conducted a survey in Chicago in which respondents were given a name and asked to assess features of the person. This was done to check that respondents identified the correct race with the racially distinctive name, but also could have been used to check whether there are perceptions of other characteristics that vary within race based on how racially distinct a name is.

suring (1) the proportion of cases in which a white tester reports more favorable treatment than a nonwhite tester reports (gross adverse treatment) or (2) the difference between the proportion of cases in which a white tester reports favorable treatment and the proportion of cases in which a nonwhite tester reports favorable treatment (net adverse treatment) (for further discussion of these measures, see Fix et al., 1993 Heckman and Siegelman, 1993 Ondrich et al., 2000 Ross, 2002). Because statistical measures are &ldquomodel-based&rdquo aggregates, net measures correctly measure the parameters in those models conditional on important stratifying variables. The gross measure may provide useful supplemental information to the net measure if the balancing disparities are large.

Ross and Yinger (2002) note that it would be valuable to know the true experiences of members of disadvantaged racial groups on average, but such information could not reveal the extent to which these individuals change their behavior to avoid experiencing discrimination. As a result, discrimination encountered by averaging over members of a disadvantaged racial group is not a complete measure of the impact of racial discrimination (Holzer and Ludwig, 2003). It is valuable to determine how much discrimination exists before such behavioral responses take place&mdashwhich is the amount estimated using paired testing&mdashand whether discrimination arises under certain circumstances.

The key observation of Murphy (2002) relates to the inferential target: Are we interested in estimating an overall or a market-level discrimination effect? Several distinct effects might be estimated, and they need to be distinguished because the estimates that result will not necessarily be identical. What is the appropriate population of real estate agents or ads from which to sample? Do we want to use only those agents that minorities actually visit? If past discrimination affects choice of agent, this population may vary from the population of agents selling houses that members of a nonwhite population could reasonably afford. Thus, the estimated effect of discrimination will be different under these alternative sampling strategies. Would it make sense to sample from agents or ads that could not reasonably be expected to be appropriate for most members of the nonwhite population? Murphy recommends ascertaining &ldquodiscrimination in situations in which Blacks are qualified buyers&rdquo (2002:72).

Auditor heterogeneity. Heckman and colleagues (Heckman, 1998 Heckman and Siegelman, 1993) also argue that average differences in treatment by race may be driven by differences in the unobserved characteristics of testers (i.e., auditor heterogeneity) rather than by discrimination. 5 Such characteristics (e.g., accent, height, body language, or physical attractiveness) of one or the other member of the pair may have a significant impact on interpersonal interactions and judgments and thus lead to invalid results (Smith, 2002). The role of these characteristics cannot be eliminated because of the paucity of observations of the research subjects. Ross (2002) addresses the problem by suggesting that, instead of trying to match testers exactly (which is virtually impossible), one can train testers to ensure that their true characteristics, as opposed to their assigned characteristics, have little influence on their behavior during the test.

Murphy (2002) addresses most of the issues raised by Heckman (1998) and discussed above. She lays out a framework showing that &ldquoas long as audit pairs are matched on all qualifications that vary in distribution by race, audit results averaged over realtors, circumstances of the visits, and auditors can be viewed as an unbiased estimate of overall-level discrimination&rdquo (Murphy, 2002:69). Murphy formally delineates the circumstances under which an estimate of discrimination will be erroneous if the researcher fails to account for individual auditor characteristics that do not vary in distribution by race and therefore were not used in the matching process.

The problem is the effect of the heterogeneity among applicants and agents. The strategy of matching on all characteristics that vary in distribution by race&mdashincluding observed, unobserved, and unobservable character-

Note that such characteristics could also lead to an understatement of discrimination.

istics&mdashsubstitutes for randomization. The problem, of course, is that we do not know whether we have in fact matched on all characteristics that vary by race. If all unmatched characteristics have the same distribution across racial groups, and if the auditors were selected to be representative of the distribution of these characteristics, we will have managed to balance the covariates across racial groups and can estimate an unbiased effect of race. But as Heckman and others note, there are a variety of reasons to believe that this goal of matching is elusive.

Heckman and Seigelman (1993) make the point that the problem of auditor heterogeneity poses a challenge particularly for employment audits, as well as for studies of wage discrimination, because the determinants of productivity within a firm are not well understood and are difficult to measure. Ross and Yinger (2002:45) note: &ldquoHeckman and Siegelman argue that matching may ultimately exacerbate the biases caused by unobserved auditor characteristics because those characteristics are the only ones on which [testers] differ however, the direction and magnitude of this type of bias [are] not known.&rdquo Heckman and his colleague further argue that the factors that employers use to differentiate applicants are not well known thus, equating testers on those factors can be difficult, if not impossible. This lack of knowledge may make experimental designs particularly problematic for labor market behaviors. However, it does not affect designs in areas with a well-known or identifiable set of legitimate cues to which establishments or authorities may respond (e.g., the rental market).

There are several other problems associated with paired testing. First, paired testing cannot be used to measure discrimination at points beyond the entry level of the housing or labor market. Examples are job assignments, promotions, discharges, or terms of housing agreements and loans. Second, the assignments and training provided to testers may not correspond to qualifications and behaviors of members of racially disadvantaged groups during actual transactions. Third, actual home or job seekers do not randomly assign themselves to housing agents or employers but select them for various reasons. Finally, different employees in the same establishment may behave differently. If a rental office has more than one agent who shows apartments, different experiences of the members of the pair may be traceable to differences in the behavior of the agent with whom they dealt.

Addressing the Limitations of Audit Studies

Ross and Yinger (2002) offer several options for addressing the limitations of audit studies. Three of the approaches they identify to address the problem of accuracy are (1) broaden the sampling frame to encompass methods other than newspaper advertisements (e.g., searching neighborhoods for rental or help-wanted signs) (2) examine whether the characteristics of

the specific goods or services involved (e.g., housing unit) instead of the characteristics of the testers affect the probability of discrimination (Yinger, 1995) and (3) use actual characteristics&mdashas opposed to assigned characteristics&mdashof testers and determine whether controlling for these characteristics influences estimates of discrimination.

To address validity concerns, Ross and Yinger (2002) suggest a strategy of sending multiple pairs to each establishment, which would allow researchers to obtain the data needed to reduce the effects of the idiosyncratic characteristics of single pairs of testers. Testers could then be debriefed after each experience to determine the agent with whom they had dealt. Doing so would not remove the potential effect of different agents on the results obtained, but it would allow researchers to assess that effect. Use of additional pairs of testers would also address issues regarding the calculation of outcome measures. Using multiple pairs might help in distinguishing systematic from random behaviors of an establishment and should, at the very least, tighten the bounds one might calculate on the basis of different mathematical formulas. Of course, care would need to be taken to avoid sending so many pairs of confederates that the research would become obvious.

Another approach to addressing the limitations of omitted variables is to collect extensive information on the actual characteristics of testers, as opposed to assigning their characteristics, and to determine whether controlling for these characteristics influences estimates of discrimination. HUD&rsquos national audit study of housing discrimination, conducted in 2000, explicitly collected information on many actual characteristics of testers, such as their income (as opposed to the income assigned to them for the study), their education, and their experience in conducting tests. 6


True experiments involve manipulation of the variable hypothesized to be causal, random assignment of participants to the experimental condition, and control of confounding variables. Experimental methods potentially provide the best solution to addressing causal inference (e.g., assigning disparate racial outcomes to discrimination per se) because well-designed and well-executed experiments have high levels of internal validity. In the language of contemporary statistics, experiments come closest to addressing the counterfactual question of how a person would have been treated but for his or her race, although they do not do so in a form that is easily translatable into direct measurement of the discriminatory effect.

Results based on analyses of this information are available at [accessed August 19, 2003].

The experimental method faces challenges when applied to race, which cannot be randomly assigned to an actual person. Experimental researchers frequently manipulate racial cues (e.g., racial designations or photographs on a résumé) or train black and white confederates to respond in standard ways. In both approaches, an attempt is made to manipulate apparent race, while holding all other variables constant, and to elicit a response from the participants. Although the experimental method has uncovered many subtle yet powerful psychological mechanisms, a laboratory experiment does not address the generalizability or external validity of its effects. Therefore, it is unable to estimate what proportion of observed disparities is actually a function of discrimination.

Over the past two decades, laboratory experiments have focused more on measuring subtle forms of bias and nonverbal forms of discriminatory behavior and less on examining overt behaviors, such as assisting others. If laboratory studies were to be more focused on real-world-type behaviors, they could help analysts who use statistical models for developing causal inferences from observational data (see Chapter 7). Thus, the results of real-world-oriented laboratory studies could provide more fully fleshed-out theories of discriminatory mechanisms to guide the modeling work. In turn, real-world studies based on laboratory-developed theories could be usefully conducted to try to replicate, and thereby validate, laboratory results.

Because laboratory experiments have limited external validity, researchers turn to field experiments, which emphasize real-world generalizability but inevitably sacrifice some methodological precision. Field audit studies randomly assign experimental and control treatments (e.g., black and white apartment hunters) to units (e.g., a rental agency) and measure outcomes (e.g., number of apartments shown). Aggregated over many encounters and units of analysis, audit studies come closer than laboratory experiments to assessing levels of discrimination in a particular market. Both the accuracy and the validity of audit studies on discrimination have been questioned, however. Advocates of paired-testing and survey experiments have responded that all these limitations can be remedied.

Although generally limited to particular aspects of housing and labor markets (e.g., showing of apartments or houses and callbacks to job applicants), audit studies to measure racial discrimination in housing and employment have demonstrated useful results. It is likely that audit studies of racial discrimination in other domains (e.g., schooling and health care) could produce useful results as well, even though their use will undoubtedly present methodological challenges specific to each domain.

Recommendation 6.1. To enhance the contribution of laboratory experiments to measuring racial discrimination, public and private funding agencies and researchers should give priority to the following:

Laboratory experiments that examine not only racially discriminatory attitudes but also discriminatory behavior. The results of such experiments could provide the theoretical basis for more accurate and complete statistical models of racial discrimination fit to observational data.

Studies designed to test whether the results of laboratory experiments can be replicated in real-word settings with real-world data. Such studies can help establish the general applicability of laboratory findings.

Recommendation 6.2. Nationwide field audit studies of racially based housing discrimination, such as those implemented by the U.S. Department of Housing and Urban Development in 1977, 1989, and 2000, provide valuable data and should be continued.

Recommendation 6.3. Because properly designed and executed field audit studies can provide an important and useful means of measuring discrimination in various domains, public and private funding agencies should explore appropriately designed experiments for this purpose.

How Randomization Actually Works?

How to achieve randomization in randomized controlled trials?

Well, there are different options used by researchers to perform randomization. It can be achieved by use of random number tables given in most statistical textbooks or computers can also be used to generate random numbers for us.

If neither of these available, you can devise your own plan to perform randomization. For example, you can select the last digit of phone numbers given in a telephone directory. For example you have different varieties of rice grown in10 total small plots in a greenhouse and you want to evaluate certain fertilizer on 9 varieties of rice plants keeping one plot as a control.

You can number each of the small plots up to 9 and then you can use series of numbers like 8 6 3 1 6 2 9 3 5 6 7 5 5 3 1 and so on

You can then allocate each of three doses of fertilizer treatment (call them doses A, B, C). Now you can apply dose A to plot number 8, B to 6, and C to 3. Then you apply dose A to 1, B to 2 because dose B is already used on plot 6 and so on.

Other great research paper topics:


  1. How are the latest improvements in the automobile industry working on the protection of the environment?
  2. What makes smartphones so resistant to bugs and viruses compare to computers?
  3. What is the story behind the Internet of Things?
  4. Why didn’t vector graphics become mainstream instead of pixels?
  5. What are some advances in technology related to medicine?
  6. What are Molten Salt Nuclear Reactors?
  7. Can everything be solar powered?
  8. How are old recordings converted to new formats?
  9. What are the differences between open and closed systems?
  10. Why do smart our electronic devices get slower over time?

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  1. What do all religions have in common?
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  5. What are some main differences between Orthodox and Catholic Christians?
  6. Why did we stop believing in multiple gods?
  7. What impact do religions have on the perception of the good and the bad?
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  10. Historically speaking, what has been the impact of religions in wars?

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Social media

  1. Are social networks making us lonely and unsociable?
  2. How to protect children online?
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  4. Why do people have the need to post everything online?
  5. How to stop cyber-bullying?
  6. Can LinkedIn help people find jobs or further education?
  7. How to make a break from social media?
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  10. Who are world-famous influencers on social media?

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  2. What music to listen to when you want to relax?
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  5. What music to listen to in order to foster memorization?
  6. Why are successful musicians more prone to become drug-abusers?
  7. Who was Doris Day?
  8. Why influences the popularity of soundtracks?
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  10. What makes some music festivals more popular than others?

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  1. What are some successful anti-bullying programs at school?
  2. Is student-centred learning effective?
  3. Are there any benefits of taking a year off and what to do during the year?
  4. What visual aids can be implemented in all classrooms?
  5. What are some innovations in the USA Education system?
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  5. What health problems can be caused by emotional stress?
  6. Can have too much coffee cause health problems?
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Social issues

  1. How can immigration crises be solved?
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  3. Why are there still anti-LGBT communities and?
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  5. Is there a way to stop sex trafficking in underdeveloped countries?
  6. Is it too late to stop global warming?
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  8. Are children becoming over-dependent on technology?
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  1. Is going vegan one way to protect the environment?
  2. How can an average person contribute to saving the environment?
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  4. How is global warming affecting wildlife?
  5. How are pesticides harming bird populations?
  6. How is plastic ocean pollution harming the oxygen we breathe?
  7. What eco-friendly products are better than the original ones?
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