Statistical properties of the K-index for detecting answer copying

R.R. Meijer, Leonardo Sotaridona

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This study investigated statistical properties of the K-index (Holland, 1996) that can be used to detect copying behavior on tests. A simulation study was conducted to investigate the applicability of the K-index for small, medium, and large datasets. In addition, the Type I error rate and the detection rate of this index were compared with the copying index of J. Wollack (1997). Several approximations were used to calculate the K-index. Results show that all approximations were able to hold the Type I error rates below the nominal level. Results further show that using the copying index results in higher decision rates than the K-indices for small and medium sample sizes (100 and 500 simulees).
Original languageEnglish
Place of PublicationEnschede
PublisherUniversity of Twente
Number of pages29
Publication statusPublished - 2001

Publication series

NameOMD research report
PublisherUniversity of Twente, Faculty of Educational Science and Technology


  • Sample Size
  • Statistical Analysis
  • METIS-205697
  • Simulation
  • Cheating
  • IR-104121

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