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Weighting Test Samples in IRT Linking and Equating: Toward an Improved Sampling Design for Complex Equating PE IRT

Author(s):
Qian, Jiahe; von Davier, Alina A.; Jiang, Yanming
Publication Year:
2013
Report Number:
RR-13-39
Source:
ETS Research Report
Document Type:
Report
Page Count:
31
Subject/Key Words:
Sampling Design, Target Population, Subsample, Poststratification Equating (PE), Raking, Complete Grouped Jackknifing, Item Response Theory (IRT)

Abstract

To study the weighting effects on linking, we first selected multiple subsamples from a data set. We then compared the linking parameters from subsamples with those from the data and examined whether the linking parameters from the weighted sample yielded smaller mean square errors (MSE) than those from the unweighted subsample. To study the weighting effects on true-score equating, we also compared the distributions of the equated scores. Generally, the findings were that the weighting produced good results.

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