Item Characteristic Curve Estimation of Signal Detection Theory-Based Personality Data: A Two-Stage Approach to Item Response Modeling

Signal Detection Theory (SDT; MacMillan & Creelman, 1991) is a method of data collection that has been used for several years, which describes the decision-making strategies of individuals. However, its use has been largely restricted to experiments involving sensation and perception. The Overclaiming Questionnaire (OCQ; Paulhus & Bruce, 1990) is a scale that has been developed to measure intellectual ability and personality, using SDT as a guideline. Although the scale has been successful in measuring human characteristics such as narcissism and intelligence, it is still unclear how to measure the characteristics of the various stimuli used (e.g., item difficulty, item discrimination, etc.). In some ways, this is a direct consequence of the general lack of research involved in item parameter estimation in the field of SDT. Using the OCQ, this article presents a graphical and nonparametric form of item response modeling to address this issue. In many ways, the approach is influenced by and structured around item response theory (IRT; Hambleton, Swaminathan, & Rogers, 1991). The general features of both SDT and IRT are described. Results suggest that this method is indeed a reasonable approach to describing item functioning, and there are several advantages to using this method over traditional IRT methods. Furthermore, SDT appears to be a fruitful approach to assessing intelligence, ability, and other psychological constructs, with advantages over traditional approaches. Overall, the results provide interesting implications for item selection and test development in several scientific and academic fields.