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ERIC Number: ED501105
Record Type: Non-Journal
Publication Date: 2008-Mar-28
Pages: 42
Abstractor: Author
A Paradox between IRT Invariance and Model-Data Fit When Utilizing the One-Parameter and Three-Parameter Models
Custer, Michael; Sharairi, Sid; Yamazaki, Kenji; Signatur, Diane; Swift, David; Frey, Sharon
Online Submission, Paper presented at the Annual Meeting of the American Educational Research Association (New York, NY, Mar 24-28, 2008)
The present study compared item and ability invariance as well as model-data fit between the one-parameter (1PL) and three-parameter (3PL) Item Response Theory (IRT) models utilizing real data across five grades; second through sixth as well as simulated data at second, fourth and sixth grade. At each grade, the 1PL and 3PL IRT models were run with each of three ability groups; low, middle and high utilizing PARSCALE Version 4.1. Results were compared in terms of item fit as well as Pearson and Spearman rank-order correlations between estimated item and ability parameters. At each grade, the 3PL exhibited the best model-data fit. However, the 1PL produced a greater degree of item and ability invariance across the three ability groups. (Contains 13 tables.)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A