A large percentage of retested cases show IQ variations large enough to change their classification, demonstrating the injustice of disposing of persons on the basis of a single test¶
Claim · All claims
Evidence · 1 study · associationalr1·q2
Currency · newest study 1921 · not yet checked against its sources · not reviewed by a person
Subclaims¶
Reading the evidence codes
q is the design tier, i the impact, n the sample, and the kind with its r
the rigour judged within that kind: what each code means.
This claim: no standardized effect is recorded in observations/ for it yet, so no benchmark reading is possible.
q2 i? A large percentage of cases shows IQ variations between tests that operate to change the classification, so disposing of persons under suspicion of mental defect on a single test is unjust. → Poull 1921
Evidence¶
Poull 1921¶
Poull, L. E. (1921). Constancy of the I.Q. in mental defectives according to the Stanford revision of Binet tests. Journal of Educational Psychology, 12(6), 323–324. https://doi.org/10.1037/h0071851
q2 · i? · associational · r1
Interpretation of the retest change distribution from the 126-case institutional sample: the article states "A large percentage of the cases shows variations which operate to change the classification"; no exact percentage or effect size is printed.
"The injustice of disposing of persons under suspicion of mental defect on the basis of a single test is clearly demonstrated. A large percentage of the cases shows variations which operate to change the classification"
Discussion¶
Related Claims¶
- The distribution of IQ changes among mental defectives does not differ from Terman's curve for unselected school children, indicating mental defectives are not more variable than normal subjects — related
- On retest, institutionalized mental defectives as a group show no IQ deterioration, with a mean change of +1.28 points and a standard deviation of 5.83 — related
- The study's conclusions rest on only sixty-five individually tested unretarded cases, limiting generalization — related
- Children whose low first IQs reflected linguistic or environmental deficiency showed substantial IQ gains after gaining command of English or schooling — a narrower finding that bears on this claim
- Clinic cases retested within less than a month to 15 months show a median IQ difference of 3.5 points, with only four cases above 5 points — reports the opposite
- The question of the constancy of IQ is not settled; further studies with regular intervals and repeated tests of the same cases over a number of years are needed — a broader claim this one bears on
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
single-test-classification-unjust-iq-variation |
title |
A large percentage of retested cases show IQ variations large enough to change their classification, demonstrating the injustice of disposing of persons on the basis of a single test |
description |
A large percentage of retested cases show IQ variations large enough to change their classification, demonstrating the injustice of disposing of persons on the basis of a single test |
status |
review |
evidence_strength |
moderate |
newest_evidence |
1921 |
generated |
by process:wiki-ingest on 2026-10-25 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — poull-1921 |
Frontmatter is the page's machine-readable record — see the Schema & Guide.