Purpose: Process Assessment of the Learner (Second Edition): Diagnostics for Math (PAL-II M) is a diagnostic tool for Math Learning Disability (MLD) with 14 subtests assessing specific math skills and math-related skills. This study examined the psychometric properties of PAL-II M and compared the performance of children with and without MLD.
Materials and methods: The PAL-II M and the Learning Disability Evaluation Scale (LDES) were used as assessment instruments. The sample included 404 primary school students from Tehran and 95 children diagnosed with MLD.
Results: The results confirmed the reliability of all subtests, except the Fingerprint Writing subtest. A three-factor model provided the best fit for the data, diverging from the original two-factor structure proposed for the test. Significant differences were found in PAL-II M scores between groups with and without MLD. Quantitative and spatial working memory were the strongest differentiators between the groups (χ2 = 213.8, p < 0.001).
Conclusions: The PAL-II M demonstrated strong psychometric properties and a cohesive factor structure among Iranian students. The subscales in PAL-II M are better categorized based on specific neuropsychological functions, including processes related to calculation, visual-spatial processing, and numerical processing. Furthermore, the test effectively distinguished between children with and without MLD. The interrelationships among PAL-II M subtests align with the various subtypes of MLD. Conceptualizing mathematical competency as a cohesive process encompassing general neuropsychological functions and specific learned mathematical skills is advantageous.
Keywords: Math learning; Process assessment of learner test; learning disability; psychometric properties; working memory.