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ERIC Number: ED468956
Record Type: Non-Journal
Publication Date: 1994-Mar
Pages: 30
Abstractor: N/A
Reference Count: N/A
A Testlet-Based Examination of the LSAT. Statistical Report. LSAC Research Report Series.
Wainer, Howard
This study examined the Law School Admission Test (LSAT) through the use of testlet methods to model its inherent, locally dependent structure. Precision, measured by reliability, and fairness, measured by the comparability of performance across all identified subgroups of examinees, were the focus of the study. The polytomous item response theory model used was developed by R. Bock (1972), and for the detection of testlets, likelihood ratio tests were used. All the analyses were performed on all four sections of two parallel forms of the LSAT. The analyses show that the testlet structure of the Reading Comprehension and Analytical Reasoning sections of the LSAT has a significant effect on the statistical characteristics of the test. The testlet-based reliability of these two sections is considerably lower than that was previously calculated under the assumption of local conditional independence. The discovery suggests that, at a minimum, any reporting of section reliability ought to be modified to reflect current knowledge, and analyses of current and future forms of these sections of the LSAT ought to model the testlet structure explicitly before calculating section reliability. (Contains 2 figures, 6 tables, and 64 references.) (SLD)
Publication Type: Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: Law School Admission Council, Newtown, PA.
Identifiers - Assessments and Surveys: Law School Admission Test