6. Difference-in-Differences with Multiple Time Periods.

with Brantly Callaway.
Journal of Econometrics, Forthcoming, December 2020.
[arXiv] [pdf] [Supplementary Appendix] [R package: did] [Stata wrapper] [Slides]
Previous versions were circulated as "Difference-in-Differences with Multiple Time Periods and an Application on the Minimum Wage and Employment".

5. The Role of Parallel Trends in Event Study Settings: An Application to Environmental Economics.

with Michelle M. Marcus.
Journal of the Association of Environmental and Resource Economists, vol. 8 (2), p. 235–275, 2021.
[arXiv] [pdf] [Supplementary Appendix] [R package] [Replication files] [Slides]

4. Doubly Robust Difference-in-Differences Estimators.

with Jun Zhao
Journal of Econometrics, vol. 219 (1), p. 101-122, 2020.
[arXiv] [pdf] [Supplementary Appendix] [R package: DRDID] [Replication files] [Slides]

3. Nonparametric Tests for Treatment Effect Heterogeneity with Duration Outcomes.

Journal of Business & Economic Statistics, Forthcoming, February 2020.
[SSRN] [arXiv] [Supplementary Appendix] [ R package: kmte]
This is a revised version of my earlier draft, "Nonparametric tests for conditional treatment effects with duration outcomes", November 2014.

2. Specification Tests for the Propensity Score.

with Xiaojun Song.
Journal of Econometrics, vol. 210 (2), p. 379-404, 2019.
[SSRN] [arXiv] [R package: pstest] [Replication files]

1. Testing for Uncorrelated Residuals in Dynamic Count Models with an Application to Corporate Bankruptcy.

Journal of Business & Economic Statistics, vol. 35 (3), p. 349-358, 2017.
[Replication files available upon request]

Working Papers

[WP6]. Efficient Estimation for Staggered Rollout Designs.

with Jonathan Roth
This version: February 2021. First version: February 2021.
[arXiv] [pdf] [R (and Stata) package: staggered]

[WP5]. When Is Parallel Trends Sensitive to Functional Form?

with Jonathan Roth
This version: January 2021. First version: October 2020.
[arXiv] [pdf]

[WP4]. Specification Tests for Generalized Propensity Scores Using Double Projections.

with Xiaojun Song
March 2020.

[WP3]. Distribution Regression in Duration Analysis: an Application to Unemployment Spells.

with Miguel A. Delgado and Andrés García-Suaza.
April 2019.

[WP2]. Covariate Distribution Balance via Propensity Scores.

with Xiaojun Song and Qi Xu.
This version: April 2020. First version: August 2018.
[arXiv] [Supplementary Appendix] [R package: IPS]

[WP1]. Program Evaluation with Right-Censored Data

New Version coming soon. This version: April 2016.
[Supplementary Appendix] [R package: kmte]


Comments and Revised Findings for "Procedural justice training reduces police use of force and complaints against officers"

with Jonathan Roth, George Wood, Andrew Papachristos, and Tom Tyler.
[Summary] [Initial Letter] [Reanalysis]