Reliability Evidence for the Gibson Assessment of Cognitive Skills (GACS): A Brief Tool for Screening Cognitive Skills Across the Lifespan

Abstract

Purpose The aim of the current study was to examine and report three sources of reliability evidence for the Gibson Assessment of Cognitive Skills, a paper-based, brief cognitive screening tool for children and adults measuring working memory, processing speed, visual processing, logic and reasoning, and three auditory processing constructs: sound blending, sound segmenting, sound deletion along with work attack skills. Sample and Methods The sample (n = 103) for the current study consisted of children (n = 73) and adults (n = 30) between the ages of 6 and 80 (M = 20.2), 47.6% of which were female and 52.4% of which were male. Analyses of test data included calculation of internal consistency reliability, split-half reliability, and test–retest reliability. Results Overall coefficient alphas range from 0.80 to 0.94, producing a strong source of internal consistency reliability evidence. The split-half reliability coefficients ranged from 0.83 to 0.96 overall, producing a strong second source of reliability evidence. Across all ages, the test–retest reliability coefficients ranged from 0.83 to 0.98. For adults ages 18 to 80, test–retest reliability coefficients ranged from 0.73 to 0.99. For children ages 6 through 17, test–retest reliability coefficients ranged from 0.89 to 0.97. All correlations were statistically significant at p < 0.001, indicating strong test–retest reliability and stability across administrations. Conclusion The evidence collected for the current study suggests that the GACS is a reliable brief screening tool for assessing cognitive skill performance in both children and adults.