Randomized experiments, as developed by Esther Duflo and Abhijit Banerjee at the Abdul Latif Jameel Poverty Action Lab, offer a novel, evidence-based approach to fighting poverty. This approach is original, in that it imports the methodology of clinical trials for application in development economics. This paper examines the analogy between J-PAL’s field experiments in development economics and randomized controlled trials in medicine. RCTs and randomized field experiments are commonly treated as identical, but such treatment neglects some of the major distinguishing (...) features that make each experiment specifically apt for use in its respective field. The central claim of this paper is that the analogy between medicine and development economics is incomplete because the central dimensions of RCTs are not simply different but altogether lacking in J-PAL’s approach. This weakens both the political and the theoretical power of such experiments in development economics. (shrink)

In this paper, we critically and constructively examine the methodology of evidence-based development economics, which deploys randomized field experiments as its main tool. We describe the...

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. 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. (shrink)

Abstract : This introduction to a special issue on "Normes and normativity" emphasizes the difficulties and challenges of distinguishing between a positive approach and a normative approach to norms in economics. Collective life is organized by norms, however the mere fact that they regularly influence behaviours does not imply their desirability. A strict description of norms may require consideration of ethical issues, which may be reported by different methods; choosing among norms however is an activity of a fundamentally normative nature, (...) which questions the legitimacy of decisions and evaluations. The very possibility of a demarcation between is and ought is not straightforward. In welfare economics in particular, the standard approaches that aim to avoid value judgements (welfarism) or to isolate them (axiomatics) can be problematic. To conclude, we present the four articles in the special issue meant to illustrate these issues regarding the nature, knowledge, value of norms and the positive-normative distinction. -/- Résumé : Cette introduction à un dossier thématique sur le thème "Normes et normativité" insiste sur les difficultés et les enjeux de la distinction entre les approches positives et normatives des normes en économie. La vie collective est organisée par des normes, mais qu’elles ordonnent les comportements dans les faits n’impliquent pas qu’elles soient désirables. Une stricte description des normes peut nécessiter de prendre en compte les questions éthiques, lesquelles peuvent être traduites par différentes méthodes ; choisir les normes en revanche est une activité de nature fondamentalement normative, qui interroge la légitimité des décisions et des évaluations. La possibilité même de démarcation entre positif et normatif ne va pas de soi : en particulier en économie du bien-être, les approches standards qui visent à éviter les jugements de valeur (le welfarisme) ou à les isoler (l’axiomatique) peuvent s’avérer problématiques. Pour conclure, nous présentons les quatre articles du numéro qui illustrent ces questionnements relatifs à la nature, la connaissance, la valeur des normes et la distinction entre normatif et positif. (shrink)