Intolerance of Uncertainty Scale-12: Psychometric Properties of This Construct Among Iranian Undergraduate Students

BACKGROUND: Uncertainty intolerance (IU), the tendency to think or react negatively toward uncertain events may have implication on individuals’ mental health and psychological wellbeing. The Intolerance of Uncertainty Scale-12 (IU-12) is commonly used across the globe to measure IU, however, its’ psychometric properties are yet to be evaluated in Iran with a Persian-speaking population. Therefore, the purpose of this research was to translate and validate the IU-12 among Iranian undergraduate students. MATERIALS AND METHODS: The multi-stage cluster random sampling was employed to recruit 410 Iranian undergraduate students (260 females) from the Azad University to complete the IU-12, the Depression Anxiety Stress Scale-2, and the Penn State Worry Questionnaire in a cross-sectional design. In this study, face validity, content validity, construct validity, and concurrent validity were measured and Construct Reliability (CR) and Cronbach’s alpha were used to measure reliability. RESULTS: The impact score of the translated IU-12 indicated acceptable face validity (value of impact score was greater than 1.5). The value of Content Validity Index (CVI) and the value of Content Validity Ratio (CVR) were above 0.7 and 0.78, respectively. The values of CVI and CVR indicated the items had acceptable content validity and were deemed essential to the measure. The measurement model analysis showed the measure with two subscales had good fit indices (CMIN/df = 2.75, p < 0.01, RMSEA = 0.07, TLI = 0.94, CFI = 0.95, GFI = 0.94). A Confirmatory Factor Analysis (CFA) indicated the scale was composed of the two subscales found in the English-version of the scale (prospective anxiety and inhibitory anxiety), and no items were removed from the scale. The values of CR (0.86) and Cronbach’s alphas (0.89) showed the measure had appropriate internal consistency. CONCLUSION: The findings support the psychometric properties of the Persian version of the IU-12. This scale could be used to reliably and accurately measure uncertainty intolerance among undergraduate students in Iran.