Rasch analysis of the Trypophobia Questionnaire

OBJECTIVE: This study aimed to assess Rasch-based psychometric properties of the Trypophobia Questionnaire measuring proneness to trypophobia, which refers to disgust and unpleasantness induced by the observation of clusters of objects (e.g., lotus seed pods). RESULTS: Rasch analysis was performed on data from 582 healthy Japanese adults. The results suggested that Trypophobia Questionnaire has a unidimensional structure with ordered response categories and sufficient person and item reliabilities, and that it does not have differential item functioning across sexes and age groups, whereas the targeting of the scale leaves room for improvements. When items that did not fit the Rasch model were removed, the shortened version showed slightly improved psychometric properties. However, results were not conclusive in determining whether the full or shortened version is better for practical use. Further assessment and validation are needed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13104-018-3245-5) contains supplementary material, which is available to authorized users.