Theoretical and Clinical Foundations of the WISC-V Index Scores

The Fallacy of Using the National Assessment Program–Literacy and Numeracy (NAPLAN) Data to Identify Australian High-Potential Gifted Students

“…In some instances (e.g., twice-exceptionality), and for some IQ assessments (e.g., the WISC), the General Abilities Index (GAI) can be a more useful description of an individual's intellectual ability than the FSIQ (see Weiss et al [15] for specific details). The GAI may be preferred as an alternative way of summarizing overall ability.…”

“…The GAI may be preferred as an alternative way of summarizing overall ability. Thus, the GAI can provide different impressions of a student's overall ability when there is variability across index scores on these tests [15]. Because the GAI does not incorporate Working Memory (WM) or Processing Speed (PS) subtest scores, it may provide clarity for some individuals who score lower on these areas but who show superior intelligence in problem-solving and conceptual thinking [15].…”

“…Thus, the GAI can provide different impressions of a student's overall ability when there is variability across index scores on these tests [15]. Because the GAI does not incorporate Working Memory (WM) or Processing Speed (PS) subtest scores, it may provide clarity for some individuals who score lower on these areas but who show superior intelligence in problem-solving and conceptual thinking [15]. Variability in WM and PS subtest scores for twice-exceptional individuals occurs due to weaknesses in working memory and processing speed, which are characteristic of some disabilities, such as attentional disorders [15].…”

“…Because the GAI does not incorporate Working Memory (WM) or Processing Speed (PS) subtest scores, it may provide clarity for some individuals who score lower on these areas but who show superior intelligence in problem-solving and conceptual thinking [15]. Variability in WM and PS subtest scores for twice-exceptional individuals occurs due to weaknesses in working memory and processing speed, which are characteristic of some disabilities, such as attentional disorders [15]. In these individuals, the GAI may be higher than the FSIQ and thus capture the "maximum potential of the child being assessed", ref.…”

Sources of measurement error in pediatric intelligence testing

“…Specifically relevant for present discussion is that the WISC-V manual presents traditional metrics of reliability that are biased when multidimensionality is present (Raykov, 1997). Importantly, while an understanding of the abilities being tapped by the index and subtest scores are fundamental to using this test, these scores must also be placed in the larger context of each child and their “world.” There are a huge number of endogenous factors such as genetics and a host of external factors such as culture and education that impact not only the growth and expression of intelligence, but also performance on intelligence tests (Weiss et al, 2016).…”