Abstract
The purpose of this study was to conduct internal validity and reliability studies on the Ross Information Processing Assessment (RIPA), a battery designed to identify, describe, and quantify cognitive-linguistic deficits following traumatic brain injury (TBI). The RIPA was administered to 126 randomly selected individuals who had sustained TBI, who ranged in age from sixteen to ninety years. Race, gender, and ethnicity did not affect an individual's participation in this study. Reliability was examined by using Cronbach's alpha coefficient. Interscorer reliability relationships were examined by using percentage of agreement among scorers of the RIPA. Content validity was established through professional review for appropriateness, and through a Pearson r Factor Analysis and Intercorrelation statistics evaluation. Construct validity was conducted by correlating RIPA subtest performance for TBI vs. non-TBI individuals, and severe TBI vs. milder TBI patients; and correlation to the Woodcock-Johnson Tests of Cognitive Ability (WJ-R). Differences between groups were examined by using an analysis of variance. The RIPA demonstrates a high degree of reliability: internal consistency reliability as measured by Cronbach's alpha coefficients was.67 to.89 with an overall coefficient alpha of.85. Further, interscorer agreement was 99.5 percent. The RIPA demonstrates sound validity. Content validity of the RIPA was rated as appropriate by the professional review process. Factor analysis of the RIPA-2 suggests that the test items are loaded on one factor: immediate memory. Pearson r correlation matrix indicates that all subtests demonstrate moderately high to high intercorrelation. Construct validity analyses reveal 80 percent of the RIPA subtests demonstrate moderate to high Pearson correlation with WJ-R subtests, with 20 percent demonstrating low correlations. Analyses of variance reveal a significant difference between TBI and non-TBI individuals' performance on the RIPA subtests. However, there is no significant difference between severe and milder TBI patients' performance on the RIPA subtests--which is expected since the test items are gauged at eighth grade level. The data indicate that the Ross Information Processing Assessment (RIPA) meets reliability and validity psychometric standards and can be accepted as a standardized battery for assessing cognitive deficits following traumatic brain injury.