Understanding weight calculations in Stata’s psmatch2

If you’ve ever used psmatch2 in Stata, you know that it has one of the least useful help files ever created. I’ve always been frustrated with not understanding how the weights in psmatch2 are calculated, so I decided to sit down and figure it out. After running psmatch2 in Stata, the program creates a variable…

Power analyses for matching

A colleague at RTI asked me about power analyses for PSM, specifically, should he assume dependent samples for his power analysis? Recall that with dependent samples, we pair observations at the analysis stage. For example, we might calculate the change over time for two observations of the same individual, or compare husbands’ and wives’ perception…

Matching and complex survey data

Several people have asked me about using propensity score matching with complex surveys, and whether/how weights, PSUs and strata should be taken into account. This paper explains how to handle these issues.