To Control or Not to Control? Bias of Simple Matching vs Difference-in-Difference Maching in a Dynamic Framework
Mardi | 2010-11-09 B103 Sylvain CHABE-FERRET – libre In this paper, I examine whether the claim “the more control variables, the better” holdswhen matching in a dynamic context. I exhibit three situations where it is better todifference with respect to past outcomes rather than to control for them: DID-matchingis unbiased whereas matching on past outcomes is biased. I also study the special caseof evaluating a job training program, borrowing a credible selection rule from Heckman,LaLonde, and Smith (1999) and relying […]