PRI was divided into VSI and FRI
The largest change from WAIS-IV to WAIS-5 is that the Perceptual Reasoning Index (PRI) was divided into a Visual Spatial Index (VSI) and a Fluid Reasoning Index (FRI).
| WAIS-IV | WAIS-5 | What the score represents |
|---|---|---|
| Verbal Comprehension Index (VCI) | Verbal Comprehension Index (VCI) | Verbal knowledge, concept formation, and verbal reasoning |
| Perceptual Reasoning Index (PRI) | Visual Spatial Index (VSI) | Analysing and constructing visual forms and understanding spatial relationships |
| Perceptual Reasoning Index (PRI) | Fluid Reasoning Index (FRI) | Finding unfamiliar rules and visual or quantitative relationships |
| Working Memory Index (WMI) | Working Memory Index (WMI) | Holding information temporarily while manipulating or updating it |
| Processing Speed Index (PSI) | Processing Speed Index (PSI) | Processing simple visual information quickly and accurately |
WAIS-IV combines Block Design, Matrix Reasoning, and Visual Puzzles in PRI. WAIS-5 uses Block Design and Visual Puzzles for VSI and Matrix Reasoning and Figure Weights for FRI.
A difference that required looking inside PRI at the subtest level in WAIS-IV can therefore appear directly as a VSI–FRI difference in WAIS-5. WAIS-5 makes the structure of visual-spatial ability and fluid reasoning clearer.
Visual working memory was added
WAIS-IV WMI is built mainly from auditory tasks. WAIS-5 primary WMI also uses auditory information through Digit Sequencing and Running Digits, but the edition adds two visual working-memory subtests:
| Subtest | Main task demand |
|---|---|
| Symbol Span | Remembering visual symbols and their positions |
| Spatial Addition | Retaining and manipulating spatial information while combining displays |
Together these can produce the Visual Working Memory Index, separating visual-spatial storage and manipulation from the auditory working-memory demands emphasized in the primary WMI.
FSIQ changed from 10 subtests to 7
| Change in WAIS-5 FSIQ | Subtests |
|---|---|
| Retained from WAIS-IV FSIQ | Similarities, Vocabulary, Block Design, Matrix Reasoning, Coding |
| Added | Figure Weights |
| Separated from the former Digit Span structure | Digit Sequencing |
| No longer used for FSIQ | Information, Visual Puzzles, Arithmetic, Symbol Search |
Visual Puzzles and Symbol Search remain primary subtests for VSI and PSI, while Information and Arithmetic remain as secondary subtests. They are no longer used in the FSIQ calculation.
Seven subtests produce WAIS-5 FSIQ, while ten primary subtests produce its five primary indexes. What FSIQ means explains how the overall score and index profile work together.
The full subtest set grew from 15 to 20
WAIS-IV contains 10 core and 5 supplemental subtests. WAIS-5 contains 10 primary and 10 secondary subtests.
| Change | Subtests |
|---|---|
| Added in WAIS-5 | Running Digits, Set Relations, Naming Speed Quantity, Symbol Span, Spatial Addition |
| Digit Span divided into separate subtests | Digit Sequencing, Digits Forward, Digits Backward |
| Not retained in WAIS-5 | Picture Completion, Cancellation |
| Moved to primary status | Figure Weights |
| Moved to secondary status | Information, Arithmetic |
The examiner selects primary and secondary subtests according to the assessment question, so the full set of 20 is not administered in every assessment.
Ancillary indexes allow finer distinctions
WAIS-5 has 15 ancillary indexes, including GAI and CPI. They allow the assessment to distinguish additional domains, auditory from visual working memory, registration from manipulation, and performance with reduced motor or verbal demands.
This gives the examiner more ways to test an explanation for an uneven profile instead of forcing different task conditions into one broad score. GAI and CPI explains two of the most widely used composites.