Equating Test Scores (without IRT) IRT
- Author(s):
- Livingston, Samuel A.
- Publication Year:
- 2004
- Source:
- Book; Princeton, NJ: Educational Testing Service
- Document Type:
- Book
- Page Count:
- 68
- Subject/Key Words:
- Item Response Theory (IRT), Test Scores, Equating Methods, Linear Equating Method, Equipercentile Equating, Data Collection, Equating, Tucker, Ledyard R, Scaled Scores, Raw Score, Statistics, Score Distribution, Standard Deviation, Correlation, Percentile Rank, Test Equating
Abstract
This booklet is essentially a transcription of a half-day class on equating that I teach for new statistical staff at ETS.The class is a nonmathematical introduction to the topic, emphasizing conceptual understanding and practical applications. The topics include raw and scaled scores, linear and equipercentile equating, data collection designs for equating, selection of anchor items, and methods of anchor equating. I begin by assuming that the participants do not even know whatequating is. By the end of the class, I explain why the Tucker method of equating is biased and under what conditions. In preparing this written version, I have tried to capture as much as possible of the conversational style of the class. I have included most of the displays projected onto the screen in the front of the classroom. I have also included the tests that the participants take during the class.