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Documentation for the ScoreDiff R Function MIRT

Author(s):
Sinharay, Sandip
Publication Year:
2019
Report Number:
RM-19-05
Source:
ETS Research Memorandum
Document Type:
Report
Page Count:
19
Subject/Key Words:
Likelihood Ratio Test, Score Differencing, Cheating, Testing Fraud, Wald Test, Mixed-Format Test, Item Performance, Preknowledge, Multidimensional Item Response Theory (MIRT), R (Computer Program Language)

Abstract

This research memorandum introduces documentation for ScoreDiff, which is a function written in R. The function can be used to compute three statistics that can be used to implement score differencing for mixed-format tests, that is, tests that include both dichotomous and polytomous items. The three statistics include the Wald or Z statistic, the signed likelihood ratio (SLR) statistic, and the modified SLR statistic.

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