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This service applies to problems in using the software and does not include statistical consultation.
Documentation
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Installation and set-up
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Some models are very complex and will require longer run times. If you are working with multidimensional models, you can try increasing the number of processors available to flexMIRT™ (default is 1) or decreasing the number of quadrature points provided that the reduced precision of numerical integration does not substantially degrade the estimation quality and stability (default is 49 points over the range -6 to 6). These things can be accomplished, respectively, by using statements such as Processors = 3; and Quadrature = 21, 5.0; for example, in the <Options> section of your flexMIRT™ syntax.
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If providing guessing values for the 3PL, the values in the -prm 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 flexMIRT™.
Due to several questions regarding conversion of the GPC model, this zip file contains details regarding the Nominal model that flexMIRT™ uses, a labeled example of a -prm file for GPC items, and an example of the conversions needed to go from more typical GPC parameters to the parameters flexMIRT™ expects in the -prm file for scoring.
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