ERIC Number: ED467817
Record Type: Non-Journal
Publication Date: 1999-Aug
Reference Count: N/A
Impact of Local Item Dependence on Item Response Theory Scoring in CAT. Law School Admission Council Computerized Testing Report. LSAC Research Report Series.
Reese, Lynda M.
This study represented a first attempt to evaluate the impact of local item dependence (LID) for Item Response Theory (IRT) scoring in computerized adaptive testing (CAT). The most basic CAT design and a simplified design for simulating CAT item pools with varying degrees of LID were applied. A data generation method that allows the LID among items to be defined was applied to generate five CAT item pools. The LID exhibited by these pools ranged from zero LID (complete local item independence) to extreme LID. Results indicate that for certain types of scoring an extreme amount of LID may adversely impact the final score obtained by the examinee. The estimated precision of the test was also affected by the extreme LID level studied here. For the medium level of LID, structured to display the amount of LID typically displayed by the Law School Admission Test, the effects of the LID were not troublesome. (Contains 8 figures and 36 references.) (SLD)
Publication Type: Reports - Research
Education Level: N/A
Authoring Institution: Law School Admission Council, Princeton, NJ.
Identifiers - Assessments and Surveys: Law School Admission Test