Mx
- Matrix algebra interpreter and numerical optimizer for structural equation modeling and other types of statistical modeling of data. Includes documentation and example code.
- http://www.vcu.edu/mx/

L-BFGS-B Nonlinear Optimization Code
- Bounded optimisation code (FORTRAN) for numerical analysis, from Northwestern University.
- http://www.ece.northwestern.edu/~nocedal/lbfgsb.html

Item Response Theory
- This website by Lawrence Rudner introduces Item Response Theory, and includes a complete on-line book.
- http://edres.org/irt/

Promoting Stakeholder Acceptance of Computer-Based Testing
- Jones (2000) article on communicating the value of and addressing issues regarding the implementation of computer-based testing.
- http://www.testpublishers.org/journal02.htm

The Reliability of Measuring Instruments
- Tom Knapp's book on reliability of measurement is freely available on this website.
- http://www.educ.ubc.ca/faculty/zumbo/series/knapp/index.htm

Bayesian Factor Analysis
- Describes the Bayesian approach to factor analysis, which incorporates prior information and eliminates the need for rotation. Includes some full-text articles.
- http://www.biophysics.mcw.edu/BRI-people/Rowe/BFA.html

Article: Increasing the Validity of Adapted Tests
- Hambleton & Patsula (1999) article providing guidelines for adapting tests for cross-cultural and international uses--includes the ITC's Test Adaptation Guidelines
- http://www.testpublishers.org/journal01.htm

PMetric Psychometric Software System
- Shareware for designing, applying, developing, and evaulating psychometric scales. The software features a scale editor, reliability analysis, central results database and other features.
- http://userpage.fu-berlin.de/~satow/psysoft.htm

Winsteps and Facets Rasch Analysis Software
- Software to construct linear measures from ordered qualitative observations. Includes details of training workshops; free student version and manual available for download.
- http://www.winsteps.com/

Structural Equation Modeling FAQ
- Frequently asked questions for the SEMNET structural equation modeling discussion group.
- http://www.gsu.edu/~mkteer/semfaq.html

Scientific Software International
- Statistical software for the social sciences. Includes LISREL for structural equation modeling, HLM for hierarchical data analysis, and BILOG, BILOG-MG, MULTILOG, PARSCALE, and TESTFACT for IRT-based test analysis.
- http://www.ssicentral.com/

Latent Variable Interactions and Quadratics
- Resources focused on latent variable interactions and quadratics. Includes a bibliography, FAQ, Excel templates, full text articles, and full text monograph.
- http://www.wright.edu/~robert.ping/research1.htm

Psychometrika
- Print journal of the Psychometric Society. Subscription and submission information and author instructions.
- http://www.psychometrika.org/

Multidimensional Scaling
- Searchable bibliography and selection of recent papers, from the University of Newcastle.
- http://www.ncl.ac.uk/mds/

Institute for Objective Measurement
- Rasch Scaling information from MESA at the University of Chicago. Includes full text articles.
- http://www.rasch.org/

Young, Forrest W.
- Emiritus Professor of Quantitative Psychology at the University of North Carolina, Chapel Hill. Includes links to the VISta data visualization software, and plenty of resources for ALSCAL multidimensional scaling, including FORTRAN source code.
- http://forrest.psych.unc.edu/

Maydeu-Olivares, Albert
- Albert Maydeu-Olivares' homepage at the University of Barcelona: includes some unpublished working papers.
- http://www.ub.es/personal/amaydeu/amaydeuen.html

Understanding Factor Analysis
- Online textbook providing overview of factor analysis, by political scientist RJ Rummel.
- http://www.hawaii.edu/powerkills/UFA.HTM

Multivariate Data Analysis
- Outline for Michael Friendly's course on multivariate data analysis and linear statistical models in behavioural science research. Includes bibliographies, computing guides, notes, and SAS examples covering topics such as regression, ANOVA, and factor ana
- http://www.psych.yorku.ca/lab/psy6140/

Ingrid Yahoo Group
- Free downloadable software for analysing repertory grids.
- http://groups.yahoo.com/group/ingrid/

Factor Analysis
- Introduction to factor analysis, with worked examples.
- http://www.psych.cornell.edu/Darlington/factor.htm

The Correlation Coefficient
- Online textbook by political scientist RJ Rummel.
- http://www.mega.nu:8080/ampp/rummel/uc.htm

Applied Psychometric Society
- Resource for professionals in psychometrics. Operated by Fordham University.
- http://www.fordham.edu/aps/

RepGrid
- Includes the Centre for Person-Computer Studies, Knowledge Support Systems, RepGrid and WebGrid software details, and the Personal Construct Psychology site. Many full-text articles for download.
- http://www.repgrid.com/

Principal Components and Factor Analysis
- Chapter from StatSoft's Electronic Statistics Textbook.
- http://www.statsoft.com/textbook/stfacan.html

Psychometrics Research Unit
- Research results, questionnaires and publications of the Psychometrics Research Unit (University of Valencia, Spain). Content a mixture of English, Spanish, Valencian and Portuguese.
- http://www.uv.es/psicometria