Psychometrika, the official journal of the Psychometric Society, is devoted to the development of psychology as a quantitative rational science. Articles examine statistical methods, discuss mathematical techniques, and advance theory for evaluating behavioral data in psychology, education, and the social and behavioral sciences generally. There are three main sections in Psychometrika: Theory and Methods, Application Reviews and Case Studies (ARCS), and Book Reviews. Additionally, there is a section online for software, data, and other electronic supplementary material for the articles in these sections.