Can We Create A Reliable and Valid Short Form of Champion Health Belief Model Questionnaire?

We aimed to create a shortened form of the Champion Health Belief Model instrument which is a widely used questionnaire about breast cancer screening behaviors with acceptable validity and reliability.
The Persian version of the Champion Health Belief Model (CHBM) instrument consists of 57 items in 8 concepts. The subjects of the study were 40 female faculty members and 34 nurses of Tehran University of Medical Sciences in 2014. Based on the results, the most influential questions in each concept were chosen and then analyzed for internal consistency and the mean scores of the concepts were compared to the original questionnaire. Next, the original form was delivered to a different population. The mean scores of each concept were compared between original and short forms. At last, the same second population was asked to fill in the shortened form in a two-week interval and a test re-test comparison was done.
In the first step, out of 57 items in the original questionnaire, 28 items were selected based on their influence on the mean score of each concept. In 40 female faculty members who were all above 40, all of the Cronbach’s alphas for all subscales were above 0.6 (ranging from 0.624 to 0.830) in the shortened form questionnaire; although they were lower than the original form. There were no significant differences between short and original questionnaires in terms of mean subscale scores. In the second step, in the second population including 34 female nurses aged over forty years in a university medical center, there was again no significant statistical difference between the 28-item and 57-item instruments. In the third step, two weeks later, the completed shortened questionnaire among 20 subjects of the same population of the nurses showed similar results, indicating the reliability of the newly design shortened form of the questionnaire.
The shortened 28-item form of the CHBM instrument seems to be both valid and reliable, and less time-consuming. Its results can be comparable to other studies that used the standard form.