A psychometric critique of nelson et al.ʹs 1990 paper: Nutrient intakes, vitamin-mineral supplementation and intelligence in british schoolchildren

(a) This critique focuses on the psychometric aspects of Nelson, Naismith, Burley, Gatenby and Geddesʹs (British Journal of Nutrition, 64, 13–22, 1990) paper. It reveals that the measures of intelligence employed by Nelson et al. had questionable validity and reliability. Furthermore, it points out the weaknesses of using a matched pairs design and a method of statistical analysis which failed to take account of regression in the analysis of the psychometric data. It is concluded that the psychometric limitations of Nelson et al.ʹs study were such that Nelson et al. were not justified in coming to a conclusion about the effect of diet on intelligence. (b) This critique focuses only on the psychometric aspects of the study by Nelson et al. (1990) because psychometrics is this authorʹs area of expertise. The critique is limited to the first part of the study, i.e. it is not concerned with that part of the study which examined the effects of diet before the study commenced.