The Indonesian version of the Life Orientation Test-Revised (LOT-R): Psychometric properties based on the Rasch model

This study aimed to validate the Indonesian version of the Life Orientation Test-Revised (LOT-R), a scale used to measure optimism. Despite being adapted in over 20 countries, its validation and adaptation reports are unavailable. This study used the rating scale model to evaluate its psychometric characteristics. The instrument was tested on 584 Indonesian high-school students aged 14 to 18 years (mean age: 16.02; SD: 1.39; 54.5% female and 45.5% male). The results indicated that the LOT-R's factor structure was unidimensional, based on the evidence from the Rasch analysis combined with a confirmatory factor analysis. Further, no local item dependence was identified. Based on the item fit statistics, all items fit the model. Nonetheless, their response categories functioned well, and the scale could reliably separate persons based on their optimism level; however, it had limitations regarding item reliability and separation because of the low number of items. Moreover, no differential item functioning was found based on gender and school type. Overall, the results indicated that this 6-item scale, including its psychometric properties, was satisfactorily reliable and valid to measure optimism in student samples, based on the Rasch analysis measurement standards. Implications and suggestions for future research have also been discussed.