Much of the methodological discussion around experiments in economics and other social sciences is framed in terms of the notions of internal and external validity. The standard view is that internal validity and external validity stand in a relationship best described as a _trade-off_. However, it is also commonly held that internal validity is a _prerequisite_ to external validity. This article addresses the problem of the compatibility of these two ideas and analyzes critically the standard arguments about the conditions under (...) which a trade-off between internal and external validity arises. Our argument stands against common associations of internal validity and external validity with the distinction between field and laboratory experiments and assesses critically the arguments that link the artificiality of experimental settings done in the laboratory with the purported trade-off between internal and external validity. We conclude that the idea of a trade-off or tension between internal and external validity seems, upon analysis, far less cogent than its intuitive attractiveness may lead us to think at first sight. (shrink)

The article identifies a latent debate in the recent literature on the role and worth of experiments in economics and other social sciences concerning the relationship between the external and the internal validity of experimental designs. Our work identifies two incompatible views regarding the relationship between internal and external validity of experiments. While in the methodological literature references to the idea that there is a trade-off between the internal and external validity of experiments abound, this view coexists with the position (...) stating that internal validity is rather a prerequisite of external validity. By identifying the contours of this implicit debate in the recent methodological literature around the use of experiments in the social sciences we call attention upon a series of insufficiently conceptualized issues regarding the central notions of internal and external validity and we question the standard view positing a trade-off between the two. This article stands against common associations of internal validity and external validity with the distinction between field and laboratory experiments and assesses critically the arguments that link the artificiality of experimental settings done in the laboratory with the purported trade-off between internal and external validity. (shrink)