Research

Working Papers

"Manipulation Robust Regression Discontinuity Designs"

Joint work with Takuya Ishihara. Current version, 2020, September 16.

Abstract

Regression discontinuity designs (RDDs) may not deliver reliable results if units manipulate their running variables. It is commonly believed that imprecise manipulations are harmless and, diagnostic tests detect precise manipulations. However, we demonstrate that RDDs may fail to point-identify in the presence of imprecise manipulation, and that not all harmful manipulations are detectable.

To formalize these claims, we propose a class of RDDs with harmless or detectable manipulations over locally randomized running variables as manipulation-robust RDDs. The conditions for the manipulation-robust RDDs may be intuitively verified using the institutional background. We demonstrate its verification process in case studies of applications that use the McCrary (2008) density test. The restrictions of manipulation-robust RDDs generate partial identification results that are robust to possible manipulation. We apply the partial identification result to a controversy regarding the incumbency margin study of the U.S. House of Representatives elections. The results show the robustness of the original conclusion of Lee (2008).

“Privatization and Productivity in China.” Revise and Resubmit at RAND Journal of Economics

Joint work with Yuyu Chen, Mitsuru Igami and Mo Xiao. Current version, 2020, August 12

Abstract

We study how changes in ownership affect the productivity of firms. Privatization of state-owned enterprises (SOEs) was a major economic reform during China's rapid growth, but its true impact remains controversial. Although private firms seem more productive than SOEs, the government selectively privatized (or liquidated) non-performing SOEs, which complicates the measurement of productivity. We address this selection problem by incorporating endogenous ownership change into a nonparametric estimation method and exploiting a lag structure in data. Results suggest privatization conferred both short-run and long-run productivity gains. The private-SOE productivity gap is larger among older firms and in less economically liberal regions.

Abstract

We propose an estimation procedure for discrete choice models of differentiated products with possibly high-dimensional product attributes. In our model, high-dimensional attributes can be determinants of both mean and variance of the indirect utility of a product. The key restriction in our model is that the high-dimensional attributes affect the variance of indirect utilities only through finitely many indices. In a framework of the random-coefficients logit model, we show a bound on the error rate of a l1-regularized minimum distance estimator and prove the asymptotic linearity of the de-biased estimator.

“Noncompliance in randomized control trials without exclusion restrictions.” Revision requested at Journal of Business & Economic Statistics.

Current version, 2020, Feb 3

(Formerly circulated as "Identification and Inference of Post-Treatment Subgroup Effects.")

Abstract

This study presents a method to identify treatment effects without exclusion restrictions for randomized experiments with non-compliance. It exploits a baseline survey that is commonly available in randomized control trials. I show the identification of the average treatment effect on the treated (ATT) and the local average treatment effect (LATE), assuming that a baseline variable maintains similar rank orders to the control outcome. I apply this strategy to a microcredit experiment with one-sided non-compliance to identify the ATT. I find that the instrumental variable (IV) estimate of log revenue is 2.2 times larger than my preferred estimate of log revenue. R package ptse is available for this analysis.

Works in Progress

"Complementarity in Couples’ Retirement : The Effect of Mandatory Retirement Age Extension"(with Mika Akesaka)

"Targeted Meta-Analysis" (with Toru Kitagawa)