Comparison of models of premorbid IQ estimation using the TOPF, OPIE-3, and Barona equation, with corrections for the...

Premorbid estimates of intellectual functioning are a key to assessment. This study aimed to compare 3 common measures and assess their accuracy: the Test of Premorbid Functioning (TOPF), Oklahoma Premorbid Intelligence Estimate (OPIE-3), and what is commonly referred to as the Barona equation. We also sought to provide appropriate adjustment considering the Flynn effect.

The sample consisted of a cross-section of 189 outpatient veterans receiving neuropsychological assessment including the TOPF and Wechsler Adult Intelligence Scale, 4th ed. (WAIS-IV). Paired sample t tests assessed differences between IQ models. Correlations for all models and actual WAIS-IV Full Scale IQ (FSIQ) to establish which model best predicted variance in current IQ. Mean differences were evaluated to establish how closely the models approximated WAIS-IV FSIQ.

The Barona equation estimated higher premorbid IQ than TOPF Simple Demographics Model; however, differences between the models were nonsignificant after a Flynn effect correction for the Barona equation (.23 IQ points per year). The OPIE-3 correlated with FSIQ but overestimated the FSIQ, demonstrating the Flynn effect. TOPF performance models (include word reading) characterized the variance of IQ scores best, but the Flynn-adjusted Barona equation had the smallest mean difference from the actual WAIS-IV FSIQ of any prediction model.

Demographic models for premorbid IQ accurately estimate IQ in adult populations when normed on the test used to measure IQ, or when adjusted for the Flynn effect. A Flynn-corrected Barona score provided a more accurate estimation of WAIS-IV FSIQ than the TOPF or the OPIE-3. (PsycINFO Database Record (c) 2020 APA, all rights reserved).