Two Strands of Field Experiments in Economics: A Historical-Methodological Analysis

Abstract

While the history and methodology of laboratory experiments in economics have been extensively studied by philosophers, those of field experiments have not attracted much attention until recently. What is the historical context in which field experiments have been advocated? And what are the methodological rationales for conducting experiments in the field as opposed to in the lab? This article addresses these questions by combining historical and methodological perspectives. In terms of history, we show that the movement toward field experiments in economics has two distinct roots. One is the general orientation of medical and social sciences to evidence-based policy evaluation, which gave rise to randomized field experiments in economics (e.g., behavioral public policy, poverty alleviation policy). The other is an awareness of several methodological limitations of lab experiments in economics, which required practitioners to get out of the lab and into the field. In these senses, the movement is a consequence of influences from both outside and inside economics: the general evidence-based trend in policy science and an internal methodological development of experimental economics. In terms of methodology, we show that these two roots resulted in two somewhat different notions of “external validity” as methodological rationales of field experiment. Finally, we suggest that analysis of experiments as exhibits highlights a methodological strategy in which both strands complement each other.

Experimental practices and objectivity in the social sciences: re-embedding construct validity in the internal–external validity distinction

“…More recently, Nagatsu and Favereau (2020) have also addressed the multiplicity of meanings of external validity. They describe the recent history of field experiments in economics as coming from two distinct intellectual traditions.…”

Experimentation in Economics

“…Although these typologies are useful in understanding how field experiments are related to laboratory ones, they do not show an important fact that the practices that economists call field experiments are not necessarily rooted in the tradition of laboratory experiments with theory-testing and establishing phenomena. Nagatsu and Favereau (2020) argue that field experiments in economics have in fact roots in two historical strands, the laboratory experimentation which wishes to systematically reduce the artificiality of laboratory setups (Lab-in-the-Field Experiments, LFEs), and the social experimentation with policy evaluation as the main goal (Randomized Field Experiments, RFEs). Philosophers discuss both strands in the context of the problem of external validity: How can we reliably infer that X causes Y in the target system from the knowledge that X causes Y in an experimental system?…”

Reflections on the 2019 Nobel Memorial Prize Awarded to Banerjee, Duflo, and Kremer

“…For a comparison between randomized field experiments and laboratory experiments in economics, seeNagatsu and Favereau (2020).…”