The Effect of Deleting Anchor on the Classification of ExamineesNERA Conference Proceedings 2008
Document TypeConference Proceeding
AbstractThe 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 InformationTia Sukin and Lisa Keller. "The Effect of Deleting Anchor on the Classification of Examinees" (2008)
Available at: http://works.bepress.com/lisa_keller/1/