NBER Publications by Ron Zimmer

This paper examines the impact of a gifted program on retention in an urban school district using a regression discontinuity design. Gifted programs often employ IQ thresholds for admission, with those above the threshold being admitted. One common problem with the RD design arises if the forcing variable (the IQ score) is manipulated, thus invalidating the standard research design. We proposed a modified RD estimator that deals with manipulation in the forcing variable. Once we properly correct for manipulation of test scores around the cut-off points, we find evidence that the gifted program offered by the district has a positive effect on retention of higher income students.

The purpose of this paper is to study identification and estimation of causal effects in experiments with multiple sources of noncompliance. This research design arises in many applications in education when access to oversubscribed programs is partially determined by randomization. Eligible households decide whether or not to comply with the intended treatment. The paper treats program participation as the outcome of a decision process with five latent household types. We show that the parameters of the underlying model of program participation are identified. Our proofs of identification are constructive and can be used to design a GMM estimator for all parameters of interest. We apply our new methods to study the effectiveness of magnet programs in a large urban school district. Our fin...