Mislevy, Robert J.2011-05-012011-05-011987Mislevy, Robert J. (1987). Exploiting auxiliary information about examinees in the estimation of item parameters. Applied Psychological Measurement, 11, 81-91. doi:10.1177/014662168701100106doi:10.1177/014662168701100106https://hdl.handle.net/11299/103395The precision of item parameter estimates can be increased by taking advantage of dependencies between the latent proficiency variable and auxiliary examinee variables such as age, courses taken, and years of schooling. Gains roughly equivalent to two to six additional item responses can be expected in typical educational and psychological applications. Empirical Bayesian computational procedures are presented and illustrated with data from the National Assessment of Educational Progress survey.enArticle