Report
Effects of Scale Transformation and Test Termination Rule on the Precision of Ability Estimates in CAT
ACT Research Report Series
Distributed by ERIC Clearinghouse
02/2000
Abstract
Error indices (bias, standard error of estimation, and root mean square error) obtained on different scales of measurement under different test termination rules in a computerized adaptive test (CAT) context were examined. Four ability estimation methods were studied: (1) maximum likelihood estimation (MLE); (2) weighted likelihood estimation (WLE); (3) expected a posteriori (EAP); and (4) maximum a posteriori (MAP). Three measurement scales (theta, number correct score, and American College Test [ACT] score scale) and three test termination rules (fixed length, fixed standard error, and target information) were studied. The findings indicate that the amount and direction of bias, standard error of estimation, and root mean square error obtained under different ability estimation methods are influenced both by measurement scale and by test termination rule in a CAT environment. WLE performed the best among the four ability estimation methods on the ACT score scale with a target information termination rule. (Contains 2 tables, 4 figures, and 21 references.) (Author/SLD)
Details
- Title: Subtitle
- Effects of Scale Transformation and Test Termination Rule on the Precision of Ability Estimates in CAT
- Creators
- Qing YiTianyou WangJae-Chun BanAmerican College Testing Program
- Resource Type
- Report
- Publication Details
- ACT Research Report Series
- Publisher
- Distributed by ERIC Clearinghouse
- Number of pages
- 28 pages
- Language
- English
- Date published
- 02/2000
- Academic Unit
- Center for Advanced Studies in Measurement and Assessment
- Record Identifier
- 9984631939602771
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