Louis Guttman's Contributions to Classical Test Theory

This article focuses on Louis Guttman's contributions to the classical theory of educational and psychological tests, one of the lesser known of his many contributions to quantitative methods in the social sciences. Guttman's work in this field provided a rigorous mathematical basis for ideas that, for many decades after Spearman's initial work, had been somewhat ambiguous and not adequately formalized. It anticipated later developments that are more widely known in education and psychology.