We consider regression discontinuity (RD) design with two, not one, running/forcing variables for a single treatment. The main identified entity is a 'double-difference-based ratio', where the numerator is a 'local difference in differences (DD)' for the response, and the denominator is a local...

In some surveys, the survey interview dates are scattered over many months. If a treatment unrelated to the survey purpose takes place during the survey period, then randomized data can obtain because individuals interviewed before and after the treatment timing are homogeneous. This happened in...

Given a binary treatment D, a response Y and covariates X, often X interacts with D in an unknown way to make the treatment effect heterogeneous. If D is exogenous, there are various semi-parametric approaches (matching, inverse probability weighting, etc.) to estimate a weighted average of the...

Given an endogenous binary treatment D, an outcome Y and covariates Z, finding an instrument for D is far from easy. Instead, this paper deals with the endogeneity using two-wave (t=1,2) panel data, assuming that the endogeneity is caused by a time-constant error δ_{i}. We postulate that Y_{it}...

Individual responses to a treatment D=0,1 differ, depending on covariates X. Averaging such a heterogeneous effect is usually done with the density of X, but the average with `overlap weight (OW)' is done "surreptitiously" with X controlled, where OW is the normalized version of PS×(1-PS) with...