Convergent, Discriminant, and Incremental Validity of Competing Measures of Functional Ability for Individuals with Traumatic Brain Injury

Utilizing a sample of individuals with traumatic brain injury (TBI; N = 40), the present study examined the relationship between performance on a well-regarded measure of functional ability, the Mayo-Portland Adaptability Inventory-IV (MPAI-IV), and a new measure, the Functional Assessment of Individuals with Brain Injury (FAIBI), for the purpose of establishing convergent and discriminant validity of the FAIBI as an effective measure of functional ability and the incremental validity of the combination of the FAIBI and the MPAI-IV.;It was posited that the FAIBI provides an important alternative to the assessment of adaptive functioning of individuals with TBI because it is administered directly to the individual who is being assessed, versus the MPAI-IV which establishes measurements via a consensus of evaluations completed by the treatment team. The purpose of this study was to demonstrate the relationship between the total and subtests of the FAIBI to items and parts of the MPAI-IV to establish the FAIBI's value as a predictor of success within a comprehensive-integrated, post-acute outpatient brain injury rehabilitation program.;Convergent and discriminant validity measures were based Pearson-product moment correlations that were computed to examine the relationship between the FAIBI total and subtest scores and the MPAI-IV Indexes and individual items. Specific correlations were referenced in the evaluation of the first two hypotheses. A hierarchical linear regression analysis was used to examine incremental validity of the FAIBI over and above the MPAI-IV part A, using the Mini Mental State Exam (MMSE) and Dementia Rating Scale-2 (DRS-2) as criterion measures.;The primary goals of this study was contribute additional empirical data relative to the validity of the FAIBI as a measure of outcome assessment in the treatment of individuals with TBI; establish the convergent and discriminant validity of the FAIBI as an effective measure of adaptive behavior; and assess the incremental validity of the FAIBI as a valid measure of adaptive functioning that can enhance the information attained via the MPAI-IV. Overall, the results of this study provide evidence of convergent, discriminant, and incremental validity between the FAIBI and MPAI-IV.