Stanford–Binet Test: Structure, Scores & the SD-16 Confusion
The SB5's five factors, its adaptive routing, and the standard-deviation change from 16 to 15 that makes old Stanford–Binet scores incomparable with new ones.
6 min read
IQ Insights
In-depth, research-based guides on IQ scores, intelligence testing, demographics and how to take a test — from the IQCognify editorial team.
Latest articles
The Highest IQ Ever Recorded: Why There Is No Answer
Guinness retired the highest-IQ record in 1990. Where the famous 228 came from, why the test's own manual capped at 170, and why no IQ above 200 is measured.
7 min read
Is Intelligence Genetic? What Heritability Really Means
Heritability rises from 20% in infancy to 80% in later adulthood — and means almost nothing people think it means. Why it depends on the society doing the measuring.
7 min read
Do Brain Training Games Work? What the Evidence Shows
11,430 people trained for six weeks and transferred nothing. Near vs far transfer, the n-back replication failure, and why the FTC fined Lumosity $2 million.
6 min read
Does IQ Predict Success? The Numbers Changed in 2022
The canonical .51 validity for cognitive ability was inflated by a flawed correction. The corrected figure is .31 — behind structured interviews and biodata.
6 min read
The WISC-V: How the Children's IQ Test Actually Works
The WISC-V Full Scale IQ comes from seven subtests, not ten — and independent factor analysis of 16 models does not support its five-factor structure.
6 min read
Spatial Reasoning: The Ability Most Tests Ignore
Spatial ability predicts STEM achievement beyond maths and verbal — and no admissions test measures it. The 217-study meta-analysis showing it can be trained.
6 min read
Verbal Reasoning: What It Measures & Why Vocabulary Predicts So Much
Verbal ability rises into your sixties, and is stable enough that clinicians use vocabulary to estimate the IQ you had before an illness. Plus where that method fails.
7 min read
Psychometrics: How Psychological Measurement Actually Works
A test is never valid — an interpretation is. Reliability, validity, standard error, norming and latent variables, explained from the governing Standards.
6 min read