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ERIC Number: ED440116
Record Type: Non-Journal
Publication Date: 2000-Feb
Pages: 42
Abstractor: N/A
Reference Count: N/A
Validating Two-Stage Course Placement Systems When Data Are Truncated. ACT Research Report Series.
Schiel, Jeff L.; Harmston, Matt
In two-stage course placement systems, students first take a screening test. Students who score at or above the screening test cutoff score "K" enroll directly in a standard college course, whereas those who score below "K" take a placement test. Students who subsequently score at or above the placement test cutoff "K1" also enroll in the standard course. Consequently, students in the standard course will not have placement scores below "K1." Moreover, placement test scores are somewhat truncated above "K1," because students who earned scores above "K" on the screening test did not have to take the placement test. Hence, their placement test scores, which likely would have equaled or exceeded "K1," are "missing." Previous research has only examined truncation on one-stage placement systems, in which it occurs below, but not above, the cutoff score. In this simulation study, the effects of truncation on estimated optimal cutoffs, accuracy rates, and success rates under different combinations of logistic regression curve, test score distribution shape, and sample size were examined for two-stage placement systems. It is shown that even when data are moderately truncated in such systems (e.g., baseline truncation below "K1" and 80% truncation above "K1"), validity statistics and optimal cutoffs can be estimated with reasonable accuracy. (Author/SLD)
ACT Research Report Series, P.O. Box 168, Iowa City, IA 52243-0168.
Publication Type: Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: American Coll. Testing Program, Iowa City, IA.