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This service applies to problems in using the software and does not include statistical consultation.
Documentation
FAQS
Can IRTPRO spreadsheet files (*ssig) be exported to SPSS, SAS, STATA, etc. formats?
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In this example we illustrate how to set up fixed item calibration with IRTPRO™, wherein some of the items have been previously calibrated and come with item parameter estimates that are assumed to be known. New items with unknown and freely estimated item parameters are also present in the analysis. This example also contains a mixture of IRT models (3PL and Graded), which is common in mixed format educational tests. (download complete example)
What is the difference in parameterizations used for common IRT models between legacy IRT programs and IRTPRO™?
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If providing guessing values for the 3PL, the values provided to IRTPRO™ will need to be logit-guessing, not typical g-parameter values. This PDF provides additional details on the parameterization of the 3PL (and GPC) in IRTPRO™.
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