Ganesh Karapakula

Yale University
New Haven, CT 06511
United States

E-Mail: EmailAddress: hidden: you can email any NBER-related person as first underscore last at nber dot org
Institutional Affiliation: Yale University

NBER Working Papers and Publications

August 2020Using a Satisficing Model of Experimenter Decision-Making to Guide Finite-Sample Inference for Compromised Experiments
with James J. Heckman: w27738
This paper presents a simple decision-theoretic economic approach for analyzing social experiments with compromised random assignment protocols that are only partially documented. We model administratively constrained experimenters who satisfice in seeking covariate balance. We develop design-based small-sample hypothesis tests that use worst-case (least favorable) randomization null distributions. Our approach accommodates a variety of compromised experiments, including imperfectly documented re-randomization designs. To make our analysis concrete, we focus much of our discussion on the influential Perry Preschool Project. We reexamine previous estimates of program effectiveness using our methods. The choice of how to model reassignment vitally affects inference.
May 2019The Perry Preschoolers at Late Midlife: A Study in Design-Specific Inference
with James J. Heckman: w25888
This paper presents the first analysis of the life course outcomes through late midlife (around age 55) for the participants of the iconic Perry Preschool Project, an experimental high-quality preschool program for disadvantaged African-American children in the 1960s. We discuss the design of the experiment, compromises in and adjustments to the randomization protocol, and the extent of knowledge about departures from the initial random assignment. We account for these factors in developing conservative small-sample hypothesis tests that use approximate worst-case (least favorable) randomization null distributions. We examine how our new methods compare with standard inferential methods, which ignore essential features of the experimental setup. Widely used procedures produce misleading in...
Intergenerational and Intragenerational Externalities of the Perry Preschool Project
with James J. Heckman: w25889
This paper examines the impact of the iconic Perry Preschool Project on the children and siblings of the original participants. The children of treated participants have fewer school suspensions, higher levels of education and employment, and lower levels of participation in crime, compared with the children of untreated participants. Impacts are especially pronounced for the children of male participants. These treatment effects are associated with improved childhood home environments. The intergenerational effects arise despite the fact that families of treated subjects live in similar or worse neighborhoods than the control families. We also find substantial positive effects of the Perry program on the siblings of participants who did not directly participate in the program, especially ...
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