WISC-V Ancillary Indexes: GAI, CPI, NVI, QRI, and AWMI Explained

What Ancillary Indexes Are

The five primary WISC-V indexes (VCI, VSI, FRI, WMI, PSI) and the Full Scale IQ are standard scores that typically appear in WISC-V evaluation reports. The ancillary indexes are additional composites that recombine subtests in different groupings to answer clinical questions the primary indexes cannot address on their own.

Ancillary indexes are not automatically calculated. The evaluator scores them when the referral question or the child's profile calls for them — typically when the FSIQ is not interpretable due to large index scatter, when gifted eligibility depends on an alternative composite, or when the evaluator needs to isolate a specific cognitive dimension.

The Five Ancillary Indexes

General Ability Index (GAI)

Subtests: Similarities, Vocabulary, Block Design, Visual Puzzles, Matrix Reasoning, Figure Weights (the six reasoning subtests from VCI, VSI, and FRI)

What it measures: General reasoning and conceptual ability with working memory and processing speed demands removed.

When it matters: The GAI is the most frequently used ancillary index. It is useful when the FSIQ is depressed by low WMI or PSI scores and the evaluator needs a composite that reflects the child's reasoning capacity without being pulled down by efficiency deficits. The National Association for Gifted Children recommends considering alternative composites such as the GAI for gifted identification in twice-exceptional children. In disability eligibility evaluations, it can add information when the FSIQ misrepresents the child's profile, but it is not an eligibility decision by itself.

Cognitive Proficiency Index (CPI)

Subtests: Digit Span, Picture Span, Coding, Symbol Search (the four efficiency subtests from WMI and PSI)

What it measures: The speed and accuracy with which a child processes and manipulates information — cognitive efficiency.

When it matters: The CPI is the counterpart to the GAI. The GAI-CPI discrepancy is the most clinically interpretable comparison on the WISC-V. A large gap (GAI significantly above CPI) is characteristic of ADHD, dyslexia, and 2e profiles. A small gap suggests the child's reasoning and processing efficiency are relatively balanced.

Nonverbal Index (NVI)

Subtests: Block Design, Visual Puzzles, Matrix Reasoning, Figure Weights, Picture Span, Coding (six subtests that require no verbal expression or receptive language)

What it measures: Overall cognitive ability estimated entirely through nonverbal tasks.

When it matters: The NVI can be useful for children whose verbal scores are depressed by factors that do not reflect reasoning ability — expressive language disorder, developmental language delay, selective mutism, significant speech dyspraxia, or English learner status. Using the FSIQ for a child whose language skills affect performance may underestimate their reasoning ability. The NVI provides a nonverbal estimate of overall cognitive capacity.

Quantitative Reasoning Index (QRI)

Subtests: Figure Weights and Arithmetic

What it measures: Nonverbal and verbal quantitative reasoning — the ability to apply mathematical logic and detect numerical relationships.

When it matters: The QRI is useful when mathematical ability is the clinical question. A child struggling in math class may have a low QRI despite adequate FSIQ, pointing to a specific quantitative processing weakness rather than a global cognitive deficit. It combines the nonverbal quantitative reasoning of Figure Weights with the verbal mathematical reasoning of Arithmetic (an oral word-problem task administered without paper).

Auditory Working Memory Index (AWMI)

Subtests: Digit Span and Letter-Number Sequencing

What it measures: Pure auditory-verbal working memory — the ability to hold and manipulate verbally presented information without visual support.

When it matters: The standard WMI includes Picture Span (a visual task), so it blends auditory and visual working memory. The AWMI strips out the visual component. If the WMI is depressed but Picture Span is adequate, the AWMI isolates the auditory deficit more precisely. This distinction matters for accommodation planning: an auditory-specific working memory deficit calls for visual supports (written instructions, graphic organizers), while a domain-general working memory deficit may require broader accommodations.

When to Request Ancillary Indexes

Parents cannot score ancillary indexes themselves — the calculations require specific conversion tables and normative data. But parents can request that the evaluator calculate them:

• GAI and CPI: When the FSIQ may be uninterpretable, ask whether the evaluator can calculate these composites and whether the index differences are statistically significant and clinically unusual under WISC-V base rates. A 15-point index discrepancy occurs in about 15% of the normative sample, so that gap alone does not establish unusual scatter or make the FSIQ uninterpretable.
• NVI: Request whenever the child's verbal expression may not reflect their reasoning ability — English learners, speech disorders, selective mutism, significant shyness during testing.
• QRI: Request when the referral involves a specific math learning disability question.
• AWMI: Request when the WMI is depressed and the evaluator administered Letter-Number Sequencing, to determine whether the deficit is auditory-specific.

If all required subtests were administered and validly scored, the evaluator can derive the additional composites from those scores without retesting. If a required subtest was not administered, additional testing may be needed.

How Ancillary Indexes Appear in the Report

Not all evaluation reports include ancillary indexes. Some evaluators only calculate the five primary indexes and the FSIQ unless specifically asked otherwise. If the report does not include ancillary composites and the profile shows significant scatter, ask the evaluator to provide them.

When ancillary indexes are reported, they appear on the same standard score scale (mean 100, SD 15) with their own confidence intervals. Compare them against each other — especially GAI vs. CPI — and against the primary indexes. The gap between ancillary composites is often more interpretable than the gap between primary indexes because each ancillary index was designed to isolate a specific cognitive dimension.

The WISC-V Score Report Decoder covers all five ancillary indexes with worked examples, explains when an alternative composite may add useful information alongside the FSIQ, and provides the questions and scripts for requesting ancillary scoring at the evaluation meeting.