Evaluating response shift in training evaluation: comparing the retrospective pretest with an adapted measurement invariance approach in a classroom management training program.

Background: Response shift (RS) can threaten the internal validity of pre-post designs. As RS may indicate a redefinition of the target construct, its occurrence in training evaluation is rather likely. The most common approach to deal with RS is to implement a retrospective pretest (then-test) instead of the traditional pre-test.