Title: A ‘Gross’ Underestimate of a ‘Massive’ IQ Rise? A Rejoinder to Flynn
Abstract: Abstract The perfonnance of a single child on an IQ-test item will disclose little about the IQ of the population from which that child has been drawn. Whether the child perfonns very well or rather poorly on the item, a sensible estimate of the child’s own IQ, and thus the population IQ, will stray but minimally from the expected population mean of 100. This is why Brand et al (1989) reported data from hundreds of children; sizeable sample sizes reduce error variance and allow much less regressed estimates of population values. Following the logic of Flynn's (1990) argument — that from tiny improvements in item pass-rates we can infer massive secular gains — it could be deduced, by analogy, from tiny annual percentage increases in household expenditure on bananas that we have all enjoyed massive annual percentage pay rises. This counterfactual conclusion, like the deduction of a massive Scottish rise in Wechsler IQ since 1961, results from neglect of the distinction between individual and group data. Such inadvertence is arguably one more retrodictable product of the ‘permissive society’.
Publication Year: 1990
Publication Date: 1990-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 17
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