Abstract
Test fraud has recently received increased attention in the field of educational
testing, and the use of comprehensive integrity analysis after test
administration is recommended for investigating different types of potential
test frauds. One type of test fraud involves answer copying between two
examinees, and numerous statistical methods have been proposed in the literature
to screen and identify unusual response similarity or irregular response
patterns on multiple-choice tests. The current study examined the classification
performance of answer-copying indices measured by the area under the receiver
operating characteristic (ROC) curve under different item response theory (IRT)
models (one- [1PL], two- [2PL], three-parameter [3PL] models, nominal response
model [NRM]) using both simulated and real response vectors. The results
indicated that although there is a slight increase in the performance for low
amount of copying conditions (20%), when nominal response outcomes were used,
these indices performed in a similar manner for 40% and 60% copying conditions
when dichotomous response outcomes were utilized. The results also indicated
that the performance with simulated response vectors was almost identically
reproducible with real response vectors.
