Chalmers recently published a critique of the use of ordinal a[alpha] proposed in Zumbo et al. as a measure of test reliability in certain research settings. In this response, we take up the task of refuting Chalmers' critique. We identify three broad misconceptions that characterize Chalmers' criticisms: (1) confusing assumptions with…

The vast majority of measures have, at their core, a purpose of personal and social change. If test developers and users want measures to have personal and social consequences and impact, then it is critical to consider the consequences and side effects of measurement in the validation process itself. The consequential basis of test interpretation…

Presents a model of tests and measurement that identifies test scores with Hilbert space vectors and true and error components of scores with linear operators. This geometric point of view brings to light relations among elementary concepts in test theory, including reliability, validity, and parallel tests. (Author/SLD)

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,…

E. Roskam's (1985) conjecture that steeper item characteristic curve (ICC) "a" parameters (slopes) (and higher item total correlations in classical test theory) would be found with more concretely worded test items was tested with results from 925 young adults on the Eysenck Personality Questionnaire (H. Eysenck and S. Eysenck, 1975).…