When I try using cem in Stata 10, I get the error "no variables defined in option treatment(), r(111);" even though my syntax looks fine. (My command was "cem AGCYTYPE POPULATION region lblackproportion, tr (POLYEXAM).") The website indicates it works in version 10.

When I try using it in Stata 12, I think the program gets a little farther. But I still get the error "cem_weights not found" after the commands:

cem AGCYTYPE POPULATION region lblackproportion, tr (POLYEXAM)

reg lblackproportion POLYEXAM YP YEAR [iweight=cem_weights]

Any ideas how to troubleshoot? My best guess is that I skipped important pre-cem steps and the program is protesting that sort of human error. Perhaps the matched N (672) is too small and so I should simulate more data to produce more matches?

Many thanks,

Katelyn

Katelyn Sack, Ph.D. candidate

University of Virginia