Type I Error Rates for Parscale’s Fit Index

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Type I error rates for PARSCALE’s fit statistic were examined. Data were generated to fit the partial credit or graded response model, with test lengths of 10 or 20 items. The ability distribution was simulated to be either normal or uniform. Type I error rates were inflated for the shorter test length and, for the graded-response model, also for the longer test length when the ability distribution was uniform. In conditions in which α was inflated, it was particularly high when one or more response categories were used infrequently. Overall, PARSCALE’s fit index is not recommended for short tests.

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.