RESUMEN
Objective: In recent years, many researchers have been searching for effective cognitive factors in the development of obsessive-compulsive disorder (OCD). One of the scales designed to measure this characteristic is the contamination cognition scale (CCS) that evaluates 2 dimensions: overestimating the likelihood and severity of contamination. The aim of the present study was to evaluate the psychometric properties of the Persian version of CCS. Method : The study population of this descriptive psychometric study included students of Shahed University. A total of 490 students were selected via cluster sampling and completed the CCS. CCS was translated and back- translated before given to the students. The Obsessive Beliefs Questionnaire (OBQ) and the Padua Inventory (PI) were used. To assess the evidence for the validity of the scale, the exploratory and confirmatory factor analyses were used. The gathered data were analyzed by SPSS-22 and Amos-22 software. Results: The results of the confirmatory factor analysis (CFA) showed that one-factor model did not have adequate fitness (RMSEA>.05). Therefore, to explore the factors of this scale, exploratory factor analysis (EFA) was used, and it revealed 3 factors (public equipment, food, and restroom) for each of the dimensions (likelihood and severity). CFA by AMOS-22 confirmed the three-factor model (GFI, CFI, and NFI>.95; RMSEA<.05). Furthermore, the results supported criteria validity of CCS with the PI total score (0.56- 0.47, p<0.001) and PI-contamination subscale (0.71-0.75, p<0.001). Also, the correlation between CCS and responsibility/threat subscale of the OBQ was significant (0.47- 0.49, p<0.001) The Cronbach's alpha for likelihood dimensions total was 0.93 and it was 0.94 for severity dimension total. The composite reliability was 0.95 for the likelihood dimension and 0.96 for severity dimension of CCS. Also, the test-retest reliability after a 4-week interval was confirmed (likelihood: r = 0.78; severity: r = 0.81, p<.001). Conclusion: The results indicated that one-factor model of CCS did not have adequate fitness, but three-factor model was confirmed in both dimensions (likelihood and severity). According to the results of the present study, the reliability and validity of the Persian version of CCS were acceptable.
