Breast cancer screening beliefs questionnaire: psychometric properties of the Persian version.

Background: Valid and reliable instruments are needed to assess such beliefs, attitudes, and knowledge. This study aimed to translate Breast Cancer Screening Beliefs Questionnaire into Persian and evaluate its psychometric properties among Iranian women.
Methods: In this methodological study, the twelve-item Breast Cancer Screening Beliefs Questionnaire was translated into Persian and filled out by 1256 Iranian women. Face, content, convergent, and discriminant validity were evaluated and exploratory and confirmatory factor analyses were performed for construct validity evaluation. Reliability was also evaluated through calculating Cronbach's alpha, McDonald's omega, Average inter-item correlation, and test-retest intraclass correlation coefficient and finally, composite reliability was estimated.
Results: Three factors were extracted in factor analysis which included screening attitude, screening knowledge and perception, and screening practice. These factors explained 55.71% of the total variance of breast cancer screening beliefs. This three-factor model was confirmed in confirmatory factor analysis based on model fit indices (PCFI = 0.703, PNFI = 0.697, CMIN/DF = 2.127, RMSEA = 0.30, GFI = 0.980, AGFI = 0.998, and CFI = 0.991). Convergent and discriminant validity were also confirmed. Composite reliability and test-retest intraclass correlation coefficient were more than 0.7.
Conclusion: With a three-factor structure, the Persian Breast Cancer Screening Beliefs Questionnaire has acceptable validity and reliability and hence, can be used to evaluate Iranian women's breast cancer screening beliefs.