The promise and success of lab - field generalizability in experimental economics : A critical reply to Levitt and List ∗ Colin

This paper addresses a recent criticism of experimental economics, by Levitt and List [2007ab, 2008], that lab experimental findings may not generalize to field settings. We argue against the criticism in three ways. First, experimental economics seeks to establish a general theory linking economic factors, such as incentives, rules, and norms, to behavior. Hence, generalizability from the lab to the field is not a primary concern in a typical experiment. Second, the experimental features that could threaten lab-field generalizability are not essential for all lab experiments (except for obtrusiveness, because of human subjects protection). And even so, there is little evidence that typical lab features not necessarily undermine generalizability. Third, we review economics experiments that are specifically designed to test lab-field generalizability; most experiments demonstrated that laboratory findings could indeed be generalized to comparable field settings. ∗This paper was prepared for an NYU Methods conference and edited book. Citations from many ESA members were extremely helpful. Support from HFSP and the Gordon and Betty Moore Foundation are gratefully acknowledged. Thanks to Dan Knoepfle, Stephanie Wang, Alec Smith, and especially Rahul Bhui for research assistance, to many patient listeners, to Tim Salmon and Abigail Barr for candid feedback, and to John List for his JPE [2006] data.