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The Effect of Deleting Anchor on the Classification of Examinees
NERA Conference Proceedings 2008
  • Tia Sukin, University of Massachusetts - Amherst
  • Lisa Keller, University of Massachusetts Amherst
Document Type
Conference Proceeding
Publication Date
The presence of outlying anchor items is an issue faced by many testing agencies. This study examines the effect of removing or retaining one aberrant anchor item. The degree of aberrancy was manipulated as well as the ability distribution of examinees, and four IRT scaling methods were investigated (Mean-sigma, mean-mean, Stocking & Lord, and Haebara). The results indicate that the percent of correctly classified students was not affected by either retaining or removing the aberrant item, although the over- and under- classification of examinees was. There was no difference among the methods.
Citation Information
Tia Sukin and Lisa Keller. "The Effect of Deleting Anchor on the Classification of Examinees" (2008)
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