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A Statistical Procedure for Testing Unusually Frequent Exactly Matching Responses and Nearly Matching Responses MIRT

Haberman, Shelby J.; Lee, Yi-Hsuan
Publication Year:
Report Number:
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Multidimensional Item Response Theory (MIRT), Multiple Comparisons (Statistics), Test Security, Cheating, English Proficiency Test, Answer Keys


In investigations of unusual testing behavior, a common question is whether a specific pattern of responses occurs unusually often within a group of examinees. In many current tests, modern communication techniques can permit quite large numbers of examinees to share keys, or common response patterns, to the entire test. To address this issue, statistical methods are provided to identify examinees in a test with answers that exactly match and to assess whether such exact matches are unusual. In addition, methodology is provided to identify examinees with response patterns unusually similar to circulated keys. Application is made to a testing program.

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