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¶

Claim · All claims
Evidence · 1 study · associational r1 · q2
Currency · newest study 1922 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i? For clinic children retested at intervals from less than a month to 15 months, the median difference was 3.5 points and only four cases showed a difference of more than 5 points. → Lincoln 1922

Evidence¶

Lincoln 1922¶

Lincoln, Edward A. (1922). The Constancy of Intelligence Quotients (A Case Study). The Journal of Educational Psychology, 14, 484-495. https://archive.org/details/journalofeducat14

q2 · i? · associational · r1

Second part of the study: sixteen clinic cases examined by the Psycho-Educational Clinic staff, retested within a month to 15 months. The printed distribution shows "The median difference is 3.5, and only four cases show a difference of more than 5 points."

"The median difference is 3.5, and only four cases show a difference of more than 5 points."

Discussion¶

Related Claims¶

• 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
• The study's conclusions rest on only sixty-five individually tested unretarded cases, limiting generalization — related
• 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 — related
• 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 — reports the opposite