This study seeks to evaluate the validity of a scale intended to measure actively open-minded thinking (AOT), and to explore whether AOT can predict academic performance. The Rasch model was applied to evaluate the scale’s construct validity through the mirt package in R. Scale validation was based upon a sample of university students in Surabaya (N=424), while regression analysis to predict academic achievement was based on a sub-sampel for which data was available (n=220). Rasch analysis results suggested that the 10-item self-report scale had good construct validity, especially when measuring participants from the lower end of the trait level spectrum. AOT was found to be positively and moderately correlated with conscientiousness and openness to experience. AOT also predicted higher performance in a course which assessed students’ ability to analyse and evaluate arguments, as well as overall performance assessed by their grade point average (GPA) 18 months later. These results suggest that AOT is an important variable that can be adequately measured using a self-report instrument. Further work should focus on creating items which are more difficult to endorse.
