Investigating the Impact of Compromised Anchor Items on IRT Equating Under the Nonequivalent Anchor Test Design

Abstract

The prevalence of high-stakes test scores as a basis for significant decisions necessitates the dissemination of accurate and fair scores. However, the magnitude of these decisions has created an environment in which examinees may be prone to resort to cheating. To reduce the risk of cheating, multiple test forms are commonly administered. When multiple forms are employed, the forms must be equated to account for potential differences in form difficulty. If cheating occurs on one of the forms, the equating procedure may produce inaccurate results. A simulation study was conducted to examine the impact of cheating on item response theory (IRT) true score equating. Recovery of equated scores and scaling constants was assessed for the Stocking–Lord IRT scaling method under various conditions. Results indicated that cheating artificially increased the equated scores of the entire examinee group that was administered the compromised form. Future research should focus on the identification and removal of compromised items.