Social, Behavioral and Experimental Economics Seminar: Silvia Saccardo

Assessing Nudge Scalability: Two Lessons from Large-scale RCTs (with Hengchen Dai, Maria Han, Naveen Raja, Sitaram Vangala and Daniel Croymans) 

Abstract:
Field experimentation and behavioral science have the potential to inform policy. Yet, many initially promising ideas show substantially lower efficacy at scale, reflecting the broader issue of the instability of scientific findings. Here, we identify two important factors that can explain variation in estimated intervention efficacy across evaluations and help policymakers better predict behavioral responses to interventions in their settings. To do so, we leverage data from (1) two randomized controlled trials (RCTs; N=187,134 and 149,720) that we conducted to nudge COVID-19 vaccinations, and (2) a dataset of effect sizes of 111 nudge RCTs involving approximately 22 million people that were conducted by either academics or a government agency. Across those datasets, we find that nudges' estimated efficacy is higher when outcomes are more narrowly (vs. broadly) defined and measured over a shorter (vs. longer) horizon, which can partially explain why nudges evaluated by academics show substantially larger effect sizes than nudges evaluated at scale by the government agency. Further, we show that nudges' impact is smaller among individuals with low baseline motivation to act — a finding that is masked when only focusing on average effects. Altogether, we highlight that considering how intervention effectiveness is measured and who is nudged is critical to reconciling differences in effect sizes across evaluations and assessing the scalability of empirical findings.

Speaker bio:

Silvia Saccardo is an associate professor at the Department of Social and Decision Sciences, Carnegie Mellon University. She received her bachelor's and master's degrees in psychology from the University of Padova, Italy and her PhD in management from the University of California San Diego. Her research integrates insights from economics and psychology to uncover the drivers of behaviors that are beneficial to individuals, organizations and society. Her work spans from studying the impediments to ethical and prosocial behavior, to promoting the uptake of life-saving vaccines and healthy habits, to understanding when behavioral interventions fail to scale. Her research has been published in leading journals including Nature, Proceedings of the National Academy of Sciences, Management Science, Organizational Behavior and Human Decision Processes, Journal of European Economic Association, Games and Economic Behavior. She is the recipient of multiple grants from the National Science Foundation, the National Institute of Aging, J-PAL North America, and the Russell Sage Foundation. She is the co-founder and co-organizer of the Early Career Behavioral Economics Conference. 

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