Evaluation is a matter of judging conformity to certain values and the judgment of how healthy or diseased a person is. The 1st step in doing outcome evaluation studies of psychotherapy is to choose a reference group or public and find out what its relevant values are. Patients, clients, sponsors, and therapists constitute 4 such publics with somewhat different values. Probable value criteria for these publics are proposed and the problems of defining and collecting valid data for these criteria are discussed. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.