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Five independent studies of the prevalence of hyperactivity in five countries are compared. All used the Conners Short Parent-Teacher Questionnaire. Sample sizes were 271 (USA), 418 (New Zealand), 711 (Great Britain), 1759 (Australia), 5357 (Germany). National cut-off points ranged from 15 to 21.
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Holborow et al. (1986) studied this question.
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