ERIC Number: ED208039
Record Type: RIE
Publication Date: 1981-Apr
Reference Count: 0
IRT Versus Conventional Equating Methods: A Comparative Study of Scale Stability.
Petersen, Nancy S.; And Others
Three equating methods were compared in terms of magnitude of scale drift: equipercentile equating, linear equating, and item response theory (IRT) equating. A sample of approximately 2670 cases was selected for each pairing of a form of the Scholastic Aptitude Tests (SAT) and an anchor test. Of the two conventional equating methods, equipercentile equating was less satisfactory than linear equating. The IRT methods did not behave in the same manner for the verbal and the mathematical equating chains. For the verbal chain, the IRT methods were greatly superior to the conventional methods. For the mathematical chain, the Levine models of linear equating and the IRT concurrent method tended to give very similar results. If it were necessary to use the same equating method for both SAT-Verbal and SAT-Mathematical forms, it appears that the IRT concurrent method would be the best equating method for reducing scale drift over time. (Author/BW)
Publication Type: Speeches/Meeting Papers; Reports - Research
Education Level: N/A
Authoring Institution: N/A
Identifiers: Equipercentile Equating; Linear Equating Method; Scholastic Aptitude Test
Note: Paper presented at the Annual Meeting of the American Educational Research Association (65th, Los Angeles, CA, April 13-17, 1981).