Hi Tom, I didn't set a caliper value in the macro statement: %macro PSMatching(datatreatment=2010_treatment, datacontrol=2010_control, method=NN, numberofcontrols=2, caliper=, replacement=no, out=beaconated_matched); Based on your input, I'm starting to think that distance wasn't a factor in the dropped treatment records. Maybe the macro couldn't find matches for the 2010 treatment records from the 2010 comparison group?
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