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310 PART IV: Applied ResearchOVERVIEWIn the most general sense, an experiment is a test; it is a procedure we use tofind out something that we don’t yet know. In this sense we experiment whenwe add new ingredients to a chili recipe in order to see whether they improveits taste. We experiment with new ways to catch fish by changing the lures weuse. We experiment when we take a different route to our job in order to finda faster way to commute. As you no doubt recognize, however, these kinds ofinformal “experiments” are much different from the experiments that are typicallycarried out in psychological research. Experimental methods, unlike otherresearch techniques such as observation and surveys, are viewed as the mostefficient way to determine causation. But determining causation is not alwayseasy, and in the last few chapters you were introduced to the complexity of thetask facing researchers who seek to understand a phenomenon by discoveringwhat caused it.In this chapter we continue our discussion of experimental methods, but wefocus on experiments as they are conducted in natural settings such as hospitals,schools, and businesses. You will see that the task of drawing cause-effectconclusions in these settings often becomes even more difficult, and that newproblems arise when an investigator leaves the confines of the laboratory to doexperiments in natural settings.There are many reasons why researchers do experiments in natural settings.One reason for these “field experiments” is to test the external validityof a laboratory finding (see Chapter 6). That is, we seek to find out if atreatment effect observed in the laboratory works in a similar way in anothersetting. Other reasons for experimenting in natural settings are more practical.Research in natural settings is likely to be associated with attempts toimprove conditions under which people live and work. The government mayexperiment with a new tax system or a new method of job training for the economicallydisadvantaged. Schools may experiment by changing lunch programs,after-school care, or curricula. A business may experiment with newproduct designs, methods of delivering employee benefits, or flexible workhours. In these cases, as is true in the laboratory, it is important to determinewhether the “treatment” caused a change. Did a change in the way patientsare admitted to a hospital emergency room cause patients to be treated morequickly and efficiently? Did a college energy conservation program cause adecrease in energy consumption? Knowing whether a treatment was effectivepermits us to make important decisions about continuing the treatment, aboutspending additional money, about investing more time and effort, or aboutchanging the present situation on the basis of our knowledge of the results.Research that seeks to determine the effectiveness of changes made by institutions,government agencies, and other organizations is one goal of programevaluation.In this chapter we describe obstacles to doing experiments in natural settings,and we discuss ways of overcoming these obstacles so that true experiments aredone whenever possible. Nevertheless, true experiments are sometimes not feasibleoutside the laboratory. In these cases, experimental procedures that only