— IQ test methodology

AGCT-era Otis test: Otis Group Intelligence Scale

Audience

Historical

Publisher

Otis (1918)

What AGCT-era Otis test measures

AGCT-era Otis test is a historical cognitive assessment for historical, published by Otis (1918). 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: scored against published normative tables, with confidence intervals reported alongside point estimates.

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 AGCT-era Otis test

Strengths: Standardized, normed, and validated for the intended population.

Limitations: Susceptible to test-taking strategy effects, anxiety, time-of-day, and motivation. Standard error typically ±5 points.

Frequently asked

Who administers AGCT-era Otis test?

Trained administrators in the relevant setting (school, employer, military, etc.). Some forms can be self-administered for self-knowledge purposes.

Is AGCT-era Otis test 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 AGCT-era Otis test 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.

Other historical tests

Army General Classification Test