Social Science Statistics Blog

« June 28, 2006 | Main | July 1, 2006 »

30 June 2006

The Balance Test Fallacy in Matching Methods for Causal Inference

We've talked a lot on this blog about evaluating the quality of matching solutions when applying these matching for preprocessing, and in some of these discussions I've previewed and referenced arguments from a paper I was working on with Kosuke Imai and Liz Stuart. We have finally finished the paper. For anyone interested, you can get a copy here. The abstract follows. Comments welcome!

Matching methods are widely used to adjust for nonrandom treatment assignment when making causal inferences. In numerous articles across a diverse variety of academic fields that use matching, researchers evaluate the success of the procedure by conducting hypothesis tests, most commonly the t-test for the mean difference of each of the observed covariates between the matched treated and control groups. We demonstrate that these hypothesis tests are fallacious and discuss better alternatives.

Posted by Gary King at 7:47 AM