Students as Experimental Participants: A Defense of the "Narrow Data Base" (WP-09-05)


James N. Druckman and Cindy D. Kam

In this chapter, we investigate the extent to which using students as experimental participants creates problems for causal inference. First, we discuss the impact of student subjects on a study’s internal and external validity. In contrast to common claims—including Sear’s (1986) widely cited proclamation of students being a “narrow data base”—we argue that student subjects do not intrinsically pose a problem for a study’s external validity. Second, we use simulations to identify situations when student subjects are likely to constrain experimental inferences. We show, perhaps surprisingly, that such situations are relatively limited. Third, we briefly survey empirical evidence that provides guidance on when researchers should be particularly attuned to taking steps to ensure appropriate generalizability from student subjects. We conclude with a discussion of the practical implications of our findings. In short, we argue that student subjects are not an inherent problem to experimental research; moreover, a case can be made that the burden of proof—of student subjects being a problem—should lie with critics rather than experimenters.

James N. Druckman, Associate Professor of Political Science, Northwestern University
Cindy D. Kam, Associate Professor of Political Science, Vanderbilt University

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