WAIS-IV vs Stanford-Binet
The two most respected clinical IQ batteries — and how they actually differ.
At a Glance
| Age range | 16–90 years | 2–85+ years (full lifespan) |
| Subtests | 10 core + 5 supplemental | 10 subtests across 5 factors |
| Index structure | 4 indices (VCI, PRI, WMI, PSI) | 5 factor scores (FR, KN, QR, VS, WM) |
| Time to administer | 60–90 minutes | 45–75 minutes |
| Norm sample | 2,200 stratified (Wechsler 2008) | 4,800 stratified (Roid 2003) |
| Reliability (FSIQ) | 0.97 | 0.98 |
| Best for | Adult clinical and neuropsych work | Wider age range, especially children + low/high extremes |
| Used by | Most US clinical psychologists | Schools, gifted assessment, broad lifespan |
| Cost | Hundreds of dollars (clinical) | Hundreds of dollars (clinical) |
Overview
The WAIS-IV (Wechsler Adult Intelligence Scale) and SB5 (Stanford-Binet, 5th edition) are the two gold-standard clinical IQ batteries used worldwide. Both produce a Full Scale IQ on the same 100-mean, 15-SD scale, but they differ in age range, sub-test structure, and clinical emphasis. This page walks through where they overlap, where they diverge, and which fits which purpose.
When to Use Each
WAIS-IV
Use the WAIS-IV when assessing adults 16+ for clinical, neuropsychological, vocational, or forensic questions. Its 4-index structure is particularly strong for detecting Working Memory and Processing Speed deficits relevant to ADHD, dementia, and traumatic brain injury.
Stanford-Binet (SB5)
Use the SB5 when you need a wider age range (toddlers through elderly), gifted assessment at very high IQs, or low-functioning assessment. Its routing-test design adapts well to extreme scores where the WAIS-IV runs into ceiling/floor effects.
Both
Some clinical contexts use both — particularly for second-opinion confirmation in legal/forensic or high-stakes gifted screening. They correlate r ≈ 0.85+ but each can catch what the other misses at the extremes.
Quick Decision Tree
- Adult 16+ for clinical assessment? → WAIS-IV
- Child under 16? → SB5 (or WISC-V for school-age)
- Suspected very high IQ (gifted, 140+)? → SB5
- Suspected very low IQ or intellectual disability? → SB5
- ADHD, dementia, or processing speed concerns? → WAIS-IV
- Need lifespan continuity (child → adult)? → SB5
Frequently Asked Questions
Which has the better reliability?
Both are excellent — WAIS-IV reports FSIQ reliability of 0.97 and SB5 reports 0.98. The difference is negligible. Both meet the gold standard for psychometric reliability in clinical settings.
Do their scores convert directly?
Approximately. Both use 100-mean, 15-SD scaling, so a 115 on one usually means a 115 on the other. Correlations between simultaneous administrations run r ≈ 0.82–0.88. At the extremes (very high or very low) divergence increases.
Which captures giftedness better?
Stanford-Binet, generally. The SB5's routing-test design extends further into the high range with less ceiling compression. WAIS-IV's FSIQ ceiling around 160 vs SB5's ~225 makes SB5 the standard for gifted-identification work above IQ 130.
Which is used for school placement?
The WISC-V (the child-aged Wechsler) is most common in US schools; SB5 is the alternative when a Wechsler-family test isn't appropriate. WAIS-IV is for adults; SB5 covers from age 2 through adulthood.
Are they used outside the US?
Yes — both are translated and re-normed for many countries. The WAIS-IV is more globally used; SB5 normings exist for several major markets but coverage is uneven.
Can I take either online?
Not the actual tests — both require licensed clinician administration. Online IQ tests in WAIS or Stanford-Binet style exist for self-assessment and give a rough estimate, but formal results require in-person clinical testing.