Effects of the testing situation on item responding: Cause for concern

The effects of faking on personality test scores have been studied previous ly by comparing (a) experimental groups instructed to fake or answer honest ly, (b) subgroups created from a single sample of applicants or nonapplican ts by using impression management scores, and (c) job applicants and nonapp licants. In this investigation, the latter 2 methods were used to study the effects of faking on the functioning of the items and scales of the Sixtee n Personality Factor Questionnaire. A variety of item response theory metho ds were used to detect differential item/test functioning, interpreted as e vidence of faking. The presence of differential item/test functioning acros s testing situations suggests that faking adversely affects the construct v alidity of personality scales and that it is problematic to study faking by comparing groups defined by impression management scores.