Scaling risk-taking tendencies using item response theory in the context of prospect theory

The present experiment attempted to scale risk-taking tendencies in typical biases on questions used in the domain of behavioral finance. Psychology majors at a private university in Tokyo (N = 401) responded to a nine-item questionnaire. The results indicated that the responses to all items could be explained by prospect theory. Examination of the tetrachoric correlation coefficient between the items revealed that they were measuring the dimension of risk-taking. An exploratory categorical factor analysis of these data indicated that the order of dimensions measured by the items was one. The factor validity of the risktaking dimension was also checked. After the existence of the risk-taking factor was checked, scaling was tried, using a 2-parameter logistic item response theory (IRT) model. Item parameters and item characteristic curves were estimated. Detection of differential item function (DIF) was also attempted; the results suggested that one of the items displayed differential functions between males and females.