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

Psychol Res Behav Manag. 2021 Jan 13;14:31-40. doi: 10.2147/PRBM.S291574. eCollection 2021.


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.

Keywords: cognition; intelligence test; memory test; reading skills; reasoning test.