Equations for prorating the symptom validity scale (FBS) for the 370-item MMPI-2

Area of Science:

• Psychological assessment
• Clinical psychology
• Forensic psychology

Background:

• The Symptom Validity Scale (FBS) is a validated measure for detecting symptom over-reporting.
• Its application is primarily based on the 567-item Minnesota Multiphasic Personality Inventory-2 (MMPI-2).
• There is a need to adapt the FBS for shorter MMPI-2 forms to increase its accessibility.

Purpose of the Study:

• To evaluate the validity of the FBS using a 370-item form (FBS-S).
• To develop a method for predicting full FBS scores from FBS-S scores.
• To assess the accuracy of this prediction method.

Main Methods:

• Utilized 707 MMPI-2 protocols from diverse testing settings.
• Extracted full FBS scores and FBS-S scores.
• Performed regression analyses to predict FBS from FBS-S.

Main Results:

• The FBS-S score accurately predicts the full FBS score.
• Regression coefficients derived from FBS-S demonstrated high predictive accuracy.
• The predictive accuracy was comparable to, and slightly better than, rationally derived prorations.

Conclusions:

• The FBS-S is a reliable and valid measure for estimating symptom over-reporting.
• This shorter form enhances the practical utility of the FBS in clinical and forensic settings.
• The findings support the use of the FBS-S for symptom validity assessment when the full MMPI-2 is not administered.