Multidimensional Rasch Analysis of a Psychological Test With Multiple Subtests

Abstract

Educational and psychological tests are often composed of multiple short subtests, each measuring a distinct latent trait. Unfortunately, short subtests suffer from low measurement precision, which makes the bandwidth—fidelity dilemma inevitable. In this study, the authors demonstrate how a multidimensional Rasch analysis can be employed to take into account the information about the correlation between latent traits such that the precision of each subtest measure can be improved and the correlation between latent traits can be accurately estimated. A real data set of the 13-scale Thinking Styles Inventory was analyzed with the traditional unidimensional approach and the multidimensional approach. The results demonstrate that in contrast to the unidimensional approach, the multidimensional approach yields a much higher level of measurement precision and a more appropriate estimate for the correlation between thinking styles. In conclusion, even short subtests can yield highly precise measures such that the bandwidth—fidelity dilemma is resolved.