— IQ test methodology

WPPSI-IV: Wechsler Preschool and Primary Scale of Intelligence

Audience

Children 2-7

Publisher

Pearson

What WPPSI-IV measures

WPPSI-IV is a clinical cognitive assessment for children 2-7, published by Pearson. Like all standardized IQ instruments, scores follow a normal distribution with mean 100 and standard deviation 15 (Wechsler scale), allowing direct percentile interpretation: a score of 115 is the 84th percentile, 130 is the 98th percentile, and so on.

How it works

The test administration depends on its category: individually administered by a licensed psychologist, typically 60-90 minutes, with strict standardization of timing, instructions, and scoring.

Scoring and interpretation

All standardized IQ tests use a normed distribution: the test publisher tested a representative sample of the target population, ranked everyone's raw scores, and assigned percentiles. Your IQ score reflects your percentile within that normed sample — not an absolute measurement.

IQ 130+ = Highly Gifted / Mensa cutoff (top 2%)
IQ 120-129 = Superior (top 9%)
IQ 110-119 = High Average (top 25%)
IQ 90-109 = Average (middle 50%)
IQ 80-89 = Low Average (bottom 25%)
IQ < 70 = Intellectual Disability range (with adaptive functioning assessment)

Take an IQ test that mirrors clinical methodology

Core Brain uses IRT 3PL Bayesian scoring — the same family of methods as the WAIS and Stanford-Binet — in a 20-minute online format.

Strengths and limitations of WPPSI-IV

Strengths: Most reliable and comprehensive cognitive measurement available. Excellent for diagnosis and individual assessment.

Limitations: Requires licensed administrator, expensive ($300-800/test), and time-intensive (60-90 min).

Frequently asked

Who administers WPPSI-IV?

Licensed psychologists, neuropsychologists, or school psychologists. Cannot legally be administered by laypeople for clinical decisions.

Is WPPSI-IV accepted by Mensa?

Mensa accepts a list of approved supervised tests. Check Mensa International's current accepted tests list; many Wechsler and Stanford-Binet results qualify.

How does WPPSI-IV compare to online tests?

Online IQ tests like Core Brain use the same statistical framework (deviation IQ, mean 100 SD 15) and most are calibrated against normed distributions. They are not clinically diagnostic but approximate professionally administered tests reasonably well for healthy adults.