IIF Certified Assessment
Start IQ Test
IIF Certified Assessment
A WISC-V report does not hand back one score. It hands back six — and the headline Full Scale IQ is built from a specific seven of ten subtests, not an average of all five indexes.
A WISC-V score report does not hand a parent one number. It hands back six: a Full Scale IQ on the cover page, and five separate index scores behind it that can, and often do, tell a different story than the headline figure alone.
Every index sits on the familiar mean-100, standard-deviation-15 scale — the same scale as the Full Scale IQ itself, which is what makes the five numbers directly comparable to each other and to the headline score. About 95% of children score within two standard deviations of the mean on any given index, the 70–130 band this site’s percentile calculator converts into an exact rank against the standardization sample.
That sample is not small. Pearson standardized the WISC-V on 2,200 children in the United States, ages 6:0 through 16:11, tested between April 2013 and March 2014 and stratified to match the 2012 U.S. Census on age, sex, race and ethnicity, parental education level, and geographic region — roughly 100 boys and 100 girls at each of eleven age levels. Every index and the Full Scale IQ are scaled against that same reference group, which is what turns a raw number of correct answers into a percentile that means the same thing for a seven-year-old in one state as for a seven-year-old in another.
The fifth edition, published in 2014, restructured the test rather than simply re-norming it. The WISC-IV had combined visual-spatial and fluid-reasoning ability into one shared "Perceptual Reasoning" index. The WISC-V split that single index into the two separate index scores described above, on the reasoning that a child’s ability to assemble visual detail and a child’s ability to reason through a novel pattern are related but distinguishable skills, worth reporting separately rather than blended into one number. Supporting that split required new content: Visual Puzzles was added to isolate visual-spatial analysis, Figure Weights was added to isolate quantitative and inductive fluid reasoning, and Picture Span was added as a visual counterpart to the older, purely auditory Digit Span working-memory task.
It is tempting to assume the top-line number is just the five index scores averaged together. It is not. Pearson’s own published WISC-V test structure shows the Full Scale IQ is calculated from a specific seven of the test’s ten primary subtests: Similarities and Vocabulary from Verbal Comprehension, Block Design alone from Visual Spatial, Matrix Reasoning and Figure Weights from Fluid Reasoning, Digit Span alone from Working Memory, and Coding alone from Processing Speed. Verbal Comprehension and Fluid Reasoning each contribute two subtests to that total; Visual Spatial, Working Memory and Processing Speed contribute one apiece — so the headline score leans on verbal and fluid reasoning ability roughly twice as hard as it leans on visual-spatial skill, working memory or processing speed.
The headline number on page one is not an average of the five numbers behind it. It is a specific seven-subtest recipe that leans on verbal comprehension and fluid reasoning twice as hard as it leans on working memory or processing speed.
Our explainer on full-scale IQ versus index scores makes the general case: a single top-line score is an average across several measurements, and two of those measurements can separate sharply even when the average looks unremarkable. Put a number on it: a child scoring 120 on Verbal Comprehension — the 91st percentile — and 90 on Processing Speed — the 25th percentile — is sitting 30 points and roughly 66 percentile points apart on two indexes that both feed directly into the Full Scale IQ. Because only one subtest from Processing Speed and two from Verbal Comprehension enter that calculation, the resulting Full Scale IQ typically lands in the low-to-mid 100s — an entirely unremarkable headline number that gives no hint a 66-percentile-point gap exists directly underneath it.
Every index and the Full Scale IQ are also reported with a confidence-interval band, not a bare point score, for the same reason our piece on IQ score margin of error covers for adult tests: no single administration pins down a score with zero error, so a report gives a range, not just a point. None of this amounts to a diagnostic judgment about any individual child — that reading is for the examiner who administered the test, working from the full report.
The WISC-V’s own norms run from age 6:0 through 16:11. The same publisher’s adult scale, the WAIS, is normed starting at 16:0 — an overlapping final year in which either test can apply, so which one a 16-year-old actually sits is frequently the examiner’s judgment call based on the reason for testing, rather than a fixed cutover date.
The WISC-V is an individually administered clinical instrument, given one child at a time by a trained examiner — typically a licensed psychologist — over roughly an hour or more of one-on-one testing, a mix of timed and untimed subtests using physical manipulatives, verbal prompts and visual stimuli rather than a group answer sheet. That is a different tool, for a different purpose, than the group-administered screeners covered in our piece on CogAT and NNAT scores, which are built to screen many students quickly with paper-and-pencil or on-screen items rather than to produce the depth of profile a WISC-V report contains.
Want to see how a raw score converts to a percentile against a real reference population? Our percentile calculator runs that exact conversion, or take the full assessment for your own result.
Find your IQ score now! →Six numbers, one report: that is the WISC-V’s actual structure, and it is worth reading past the first one. Our IQ test reports its own result the same way — with the percentile attached, not just the raw score.
Verbal Comprehension, Visual Spatial, Fluid Reasoning, Working Memory and Processing Speed. Each is built from two subtests and reported on the same mean-100, SD-15 scale as the Full Scale IQ.
No. It is calculated from a specific seven of the test’s ten primary subtests — two each from Verbal Comprehension and Fluid Reasoning, and one each from Visual Spatial, Working Memory and Processing Speed — not an equal average of all five indexes.
Ages 6:0 through 16:11. The same publisher’s WAIS adult scale is normed from age 16:0, so there is a one-year overlap where either test may be used.
Yes. Index scores commonly differ by 15 points or more on the same child’s report, and this is an expected pattern given the test’s structure rather than a sign of measurement error.
Corrections: spotted an error? Email corrections@iqmetrics.org and we will update this story and note the change here.
A Full-Scale IQ is an average of several narrower index scores, and when those indexes disagree by enough, the average describes none of them well.
The two tests American schools use most to screen for gifted programmes print their results on scales that differ by one point of standard deviation. At the level where cutoffs are set, that moves the same printed number by most of a percentile.
When a large Florida district began testing every second grader instead of waiting for a teacher's nomination, the population it identified as gifted changed sharply — not because more students became capable, but because fewer of them had ever been tested at all.
Our IIF-certified assessment reports your score with its scale, percentile and confidence range — and a breakdown of the cognitive domains behind it.
Start IQ Test →
