Detect Aberrant Behavior in Test Data
Detect several types of aberrant behavior, including answer
copying, answer similarity, change point, nonparametric misfit, parametric
misfit, preknowledge, rapid guessing, and test tampering.
aberrance

The aberrance package contains a collection of functions for detecting
several types of aberrant behavior, including:
- Answer copying, using statistics such as the $\omega$ statistic
(Wollack, 1997).
- Answer similarity, using statistics such as the $GBT$ statistic
(van der Linden & Sotaridona, 2006) and the $M4$ statistic (Maynes,
2014).
- Change point, using statistics such as the likelihood ratio
test-based statistic, the score test-based statistic, and the Wald
test-based statistic (Shao et al., 2016; Sinharay, 2016; Tu et al.,
2023).
- Nonparametric misfit, using statistics such as the $ZU3$ statistic
(van der Flier, 1982) and the $H^T$ statistic (Sijtsma, 1986).
- Parametric misfit, using statistics such as the standardized
log-likelihood statistic (Drasgow et al., 1985) and its various
corrections (Bedrick, 1997; Gorney et al., 2024; Molenaar & Hoijtink,
1990; Snijders, 2001).
- Preknowledge, using statistics such as the signed likelihood ratio
test statistic (Sinharay, 2017).
- Rapid guessing, using methods such as the custom threshold method
(Wise et al., 2004; Wise & Kong, 2005), the normative threshold method
(Wise & Ma, 2012), and the cumulative proportion correct method (Guo
et al., 2016).
- Test tampering, using statistics such as the erasure detection
index (Wollack et al., 2015; Wollack & Eckerly, 2017) and its
corrected versions (Sinharay, 2018).
Installation
Install the released version from CRAN:
install.packages("aberrance")
Alternatively, install the development version from GitHub:
# install.packages("devtools")
devtools::install_github("kyliegorney/aberrance")