Millsap's Psychometrics Page

Links to Professional Organizations

• The Psychometric Society, along with the journal of the Society, Psychometrika.
• Division 5 of the American Psychological Association, which is devoted to evaluation, measurement, and statistics.
• The National Council on Measurement in Education (NCME).
• The Joint Committee on Testing Practices, within the American Psychological Association.
• The American Educational Research Association (AERA).
• The National Assessment of Educational Progress (NAEP).
• The Institute for Objective Measurement, a site devoted to the Rasch model in item response theory. Many further links here.
• SIOP, the Society for Industrial/ Organizational Psychology. A resource for testing issues in employment settings.
• Society for Quantitative Analysis of Behavior, with links to mathematical sites and material.
• International Testing Commission homepage, with emphasis on multinational and cross-cultural issues in testing.
• Buros Center for Testing, which produces the Mental Measurements Yearbook and Tests in Print, two test references.
• RaschSIG website, home of the Special Interest Group for Rasch models.

Software Resources for Psychometrics

• Assessment Systems Corporation.
• Scientific Software, distributes Bilog-MG, Multilog, Parscale, and Testfact.
• Winsteps and Facets Rasch modeling software.
• FreeIRT Project, with free downloads on various aspects of IRT.
• RUMM homepage, a unidimensional Rasch program for polytomous or dichotomous item formats.

General Psychometric Sites

• Standards for Educational and Psychological Tests, by APA, AERA, NCME.
• Lawrence Rudner's IRT page, which contains Frank Baker's book "Basics of Item Response Theory" and other useful information.
• International Personality Item Pool, a "scientific collaboratory" for personality measurement.
• Jim Roberts' IRT page, with information on unfolding models and software.
• Rasch Measurement Transactions website. Archives of the Rasch Measurement SIG group in AERA.
• John Uebersax's Latent Class Analysis page, with material also on general latent trait models. Also links to his page on statistical methods for assessing rater agreement.
• Keith Markus' Latent Class Analysis page, with information on LCA software.
• Paul Barrett's Homepage, with all sorts of good stuff; software, preprints, reprints, and many links.
• L.L. Thurstone Psychometric Lab at the University of North Carolina.
• CASMA website, which is the Center for Advanced Studies in Measurement and Assessment at the University of Iowa.
• The Bear Center, or the Berkeley Evaluation and Assessment Research Center, directed by Mark Wilson. Software and publications available here.
• Henk Kiers' website, with downloads of factor analysis-related software. Henk also has material on multiway component analysis here.
• David Weiss' CAT Central website, a global resource for computerized adaptive testing research.
• The Personality Project webpage, with material on personality measurement and theory. Many links to other relevant sites.
• Jim Grice's factor score resource page, with info on computing factor scores, indeterminacy, and use of scores.
• The Measurement,Statistics, and Methodological Studies Program at ASU in the School of Education.
• Jim Ramsay's web page, with information on functional data analysis as applied to psychometric problems, among other applications.
• Warren Sarle's FAQ page on measurement, with emphasis on implications for statistics.
• Testlink, the world's largest test collection database. Operated by ETS.
• Robert Mislevy's web page, with many papers relevant to psychometrics, along with information on his assessment design work.
• CRESST website, which is the Center for Research on Evaluation, Standards, and Student Testing at UCLA. Lots of technical reports to download.
• Richard Darlington's factor analysis page, with a nice tutorial on factor analysis.
• Jim Albert's homepage, with information and software related to latent variable modeling of ordinal measures, and his book on this topic coauthored with Val Johnson.
• Jean-Paul Fox's homepage, with information and software for multilevel IRT modeling.
• Herman Aguinis' homepage for his text Regression Analysis for Categorical Moderators, containing several highly useful software programs for use with moderated regression analyses, as in comparing regressions across multiple groups.

Resources on Measurement Invariance

• The Educational Measurement Lab at the University of Illinois. This site contains information about the work of William Stout and his students and associates.
• Brian Junker's homepage. Some links to his tech reports and other measurement stuff.
• Bruno Zumbo's Differential Item Functioning Handbook website.
• The DIFDetect website, which gives a free STATA program called DIFDetect that uses ordinal logistic regression in combination with the graded response model for detecting DIF.
• The IRT Modeling Lab at the University of Illinois. A nice tutorial on item response theory (IRT), with a subsection on differential item functioning (DIF).

For the partial factorial invariance procedure described in the following paper:

Millsap, R.E. & Kwok, O.M. (2004). Evaluating the impact of partial factorial invariance on selection in two populations. Psychological Methods, 9, 93-115.

you can find the BIVAR program used in the paper here. This program finds quadrant probabilities in an arbitrary bivariate normal population.

This page is a work in progress--more to come soon!

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