Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Researchers are often interested in the relationship between treatment effects and observed individual heterogeneity. This paper proposes the first nonparametric monotonicity test for conditional treatment effects under the popular regression discontinuity framework. The proposed test examines whether the average treatment effect or the local average treatment effect has a monotonic relationship with some of the observed individual characteristics. We show consistency and asymptotic uniform size control of the proposed test, and apply the test to study treatment effect heterogeneity in two empirical settings.