Meehl and the ex post facto design

Paul E. Meehl's problem of systematic unmatching is discussed, and it is argued that his reasoning and conclusion are incorrect. Unmatching will probably occur seldom in empirical cases, and if it does take place, it will constitute some sort of undercorrection. Moreover, his attempt at interpretation of statistical control in terms of so-called "counterfactuals" is found to be misleading.