The file ScoreDiff.R includes R code for performing score differencing, which is essentially an examination of whether the performance difference of an examinee on two sets of items is statistically significant. Score differencing can be used to detect several types of test fraud including item preknowledge and fradulent erasures. More details about score differencing, its use, and its applications can be found in an ETS Research Memorandum (Sinharay, 2019). The files "SimScoresDich", "ScoresPoly", and "ItemInfDich.csv" include data files that are used in examples of applications of ScoreDiff.R described in the ETS Research Memorandum. Examples of applications of ScoreDiff.R can be found in the file "Examples.R".
R software
If you are using the ScoreDiff function in your work, you can cite it as:
Sinharay, S. (2019). Documentation for the ScoreDiff R Function. ETS Research Memorandum. Princeton NJ: ETS
@techreport{s19, author="Sinharay, S.", year=2019, title="Documentation for the ScoreDiff R Function", type="Research Memorandum", number="RM-19-xx", institution="ETS", address="Princeton, NJ" }