The measure of abnormal performance developed here to study the impact of EDI adoption, XP or ???excess performance,??? takes the general form: (4) XP = (Cpost -FCpre) -(Mpost -FMpre) where C is actual EDI-county performance (the particular performance variables are developed in more detail below), M is the actual performance of the matched portfolio of non-EDI counties, states, or other entities,