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Small-Sample Equating by the Circle-Arc Method

Author(s):
Livingston, Samuel A.; Kim, Sooyeon
Publication Year:
2008
Report Number:
RR-08-39
Source:
ETS Research Report
Document Type:
Report
Page Count:
16
Subject/Key Words:
Equating, Small Samples, Circle-Arc Method

Abstract

This paper suggests two new, related methods for estimating a test-score equating relationship from small samples of test takers. These methods do not require the estimated equating transformation to be linear. Instead, they constrain the estimated equating curve to pass through 2 prespecified end-points and a middle point determined from the data. Some preliminary results indicate that these methods outperform mean equating and other methods used for equating in small samples.

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