In adolescence research, the treatment of measurement reliability is often fragmented, and it is not always clear how different reliability coefficients are related. We show that generalizability theory (G-theory) is a comprehensive framework of measurement reliability, encompassing all other reliability methods (e.g., Pearson "r,"…

Because test scores are ordinal not cordinal attributes, the average test score often is a misleading way to summarize the scores of a group of individuals. Similarly, correlation coefficients may be misleading summary measures of association between test scores. Proper, readily interpretable, summary statistics are developed from a theory of…

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).…

This paper points out that there are certain generalizations about directions for guessing and methods of scoring that require that data be derived from random groups design. It supports the viewpoint that it is neither sufficient nor appropriate to make such generalizations on the basis of an analysis of scores obtained from the answer sheets of…

The thesis of this paper is that the decision to use one of three approaches to unit-of-analysis in educational research should be based on substantive considerations, not statistical factors. In addition to the commonly used "total analysis" (regression analysis across individuals), the within and between analyses are inherent in the…

The idea that validity should be considered a property of inferences, rather than of assessments, has developed slowly over the past century. In early writings about the validity of educational assessments, validity was defined as a property of an assessment. The most common definition was that an assessment was valid to the extent that it…