Abstract :
This study provides construct validity evidence and reliabilities (consistency and stability) for 5
misrepresentation (response distortion) scales of the Psychological Screening Inventory (PSI;
Lanyon, 1970, 1973, 1978) in assessing 3 constructs: exaggeration of psychopathology, exaggeration
of personal virtue, and exaggeration of health problems. Using data from forensic
cases, the existence and independence of these 3 constructs were confirmed in data from the
MMPI–2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) and the Balanced Inventory
of Desirable Responding (Paulhus, 1986, 1991). The PSI scales were then shown to load
highly on these constructs. The PSI scales also showed the expected patterns when their mean
scores were examined for 15 sets of responses from participant groups with varied motivations
to misrepresent. We present receiver operating characteristic data to show the success of the
scales in distinguishing between simulators and appropriate comparison groups. Using the
same data, we also present classification accuracy in terms of positive predictive power and
negative predictive power based on a sensitivity level of 90% and misrepresentation base rates
of .20 and .10.
