Ensuring Validity in International Comparisons Using State-of-the-Art Psychometric Methodologies

Researchers using quantitative methods for describing data from observational or experimental studies often rely on mathematical models referred to as latent variable models. The goal is to provide quantities that allow generalization to future observations in the same subject domain. A review of selected current and historical examples illustrates the breadth and utility of the approach, ranging from a worldwide used system for ranking chess players, to finding hidden structure in genetic data, to identifying common factors that can explain patterns of volatility of assets examined in financial modeling. This chapter describes how latent variable models are used in educational measurement and psychometrics, and in the studies of the International Association for the Evaluation of Educational Achievement (IEA) in particular. Within this domain, these models are used to construct a validity argument by modeling individual and system level differences as these relate to performance on large-scale international comparative surveys of skills, such as those commissioned by IEA.