Working Paper: NBER ID: w31982
Authors: James J. Heckman; Rodrigo Pinto; Azeem Shaikh
Abstract: This paper considers the problem of making inferences about the effects of a program on multiple outcomes when the assignment of treatment status is imperfectly randomized. By imperfect randomization we mean that treatment status is reassigned after an initial randomization on the basis of characteristics that may be observed or unobserved by the analyst. We develop a partial identification approach to this problem that makes use of information limiting the extent to which randomization is imperfect to show that it is still possible to make nontrivial inferences about the effects of the program in such settings. We consider a family of null hypotheses in which each null hypothesis specifies that the program has no effect on one of many outcomes of interest. Under weak assumptions, we construct a procedure for testing this family of null hypotheses in a way that controls the familywise error rate--the probability of even one false rejection--in finite samples. We develop our methodology in the context of a reanalysis of the HighScope Perry Preschool program. We find statistically significant effects of the program on a number of different outcomes of interest, including outcomes related to criminal activity for males and females, even after accounting for imperfections in the randomization and the multiplicity of null hypotheses.
Keywords: Imperfect Randomization; HighScope Perry Preschool Program; Partial Identification; Familywise Error Rate
JEL Codes: C31; I21; J13
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| HighScope Perry Preschool Program participation (I21) | long-term outcomes (I12) |
| unobserved characteristics (D80) | treatment assignment (C90) |
| treatment assignment (C90) | outcomes (P47) |
| availability of families for weekly home visits (J12) | treatment assignment (C90) |
| treatment assignment (C90) | criminal activity outcomes (K42) |