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ERIC Number: EJ794585
Record Type: Journal
Publication Date: 2008
Pages: 19
Abstractor: Author
Reference Count: 22
ISSN: ISSN-0022-0655
Improving Person-Fit Assessment by Correcting the Ability Estimate and Its Reference Distribution
de La Torre, Jimmy; Deng, Weiling
Journal of Educational Measurement, v45 n2 p159-177 Sum 2008
The standardized log-likelihood of a response vector (l[subscript z]) is a popular IRT-based person-fit test statistic for identifying model-misfitting response patterns. Traditional use of l[subscript z] is overly conservative in detecting aberrance due to its incorrect assumption regarding its theoretical null distribution. This study proposes a method for improving the accuracy of person-fit analysis using l[subscript z] which takes into account test unreliability when estimating the ability and constructs the distribution for each l[subscript z] through resampling methods. The Type I error and power (or detection rate) of the proposed method were examined at different test lengths, ability levels, and nominal [alpha] levels along with other methods, and power to detect three types of aberrance--cheating, lack of motivation, and speeding--was considered. Results indicate that the proposed method is a viable and promising approach. It has Type I error rates close to the nominal value for most ability levels and reasonably good power. (Contains 1 figure and 8 tables.)
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Publication Type: Journal Articles; Reports - Evaluative
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A