Investigating Factor Structure, Validity and Reliability of Thought Fusion Instrument (TFI) in Iran

Introduction: Considering the importance of fusion of thought in the persistence of symptoms of obsessive-compulsive disorder, This study was conducted to assess the validity and reliability of the TFI in Iran. Methods: In a descriptive cross-sectional study, a fusion measure was used. First, the author was allowed to use the tool and then translated into Persian. The statistical population of this study included all undergraduate students of Tehran University, that 309 students were selected by multi-stage random cluster sampling method. The data analyzed through Cronbach’s alpha and construct validity statistical method. Results: The reliability of the TFI was analyzed using Cronbach's alpha and retest method with a one month interval and its correlation coefficients were 0.93 and 0.81 at significant level (P <0.001) respectively. Validity of the TFI was estimated using factor analysis and construct validity method with implementation of Thought-Action Fusion (TAF) questionnaire. There was a positive and significant correlation coefficient between the (TFI) and (TAF) questionnaires (0.833) at significant level (P <0.001). Also, the results of exploratory factor analysis show that the three factors of thought-event fusion, thought-action fusion and thought-object fusion for the thought fusion instrument in total account for 75 percent of the variance.   Conclusion: Thought Fusion Instrument (TFI) can be a reliable and valid tool for evaluating Wells meta-cognitive theory and can be used to measure Thought Fusion style in normal or clinical samples.