ERIC Number: ED469184
Record Type: Non-Journal
Publication Date: 2002-Jul
Reference Count: N/A
Effects of Multidimensionality on IRT Item Characteristics and True Score Estimates: Implications for Computerized Test Assembly. Computerized Testing Report. LSAC Research Report Series.
Wang, Xiang-Bo; Harris, Vincent; Roussos, Louis
Multidimensionality is known to affect the accuracy of item parameter and ability estimations, which subsequently influences the computation of item characteristic curves (ICCs) and true scores. By judiciously combining sections of a Law School Admission Test (LSAT), 11 sections of varying degrees of uni- and multidimensional structures are used to assess the impact of multidimensionality on ICCs and true scores. This combination makes an artificial test for analysis purposes. It was found that multidimensionality decreased item slopes and estimated true score curves. The effect is shown to be bigger in the high ability range than in the low ability range. (Contains 23 figures and 21 references.) (Author/SLD)
Publication Type: Numerical/Quantitative Data; Reports - Research
Education Level: N/A
Authoring Institution: Law School Admission Council, Newtown, PA.
Identifiers - Assessments and Surveys: Law School Admission Test