Designing and determining validity and reliability of a questionnaire to identify factors affecting nutritional behavior among patients with metabolic syndrome

A number of studies have shown a clear relationship between diet and component of metabolic syndrome. Based on the Theory of Reasoned Action (TRA), attitude and subjective norm are factors affecting behavioral intention and subsequently behavior. The aim of the present study is to design a valid questionnaire identifying factors affecting nutritional behavior among patients with metabolic syndrome.
Via literature review, six focus group discussion and interview with nutrition specialists were performed to develop an instrument based on the theory of reasoned action. To determine validity of the instrument, content and face validity analyses with 15 expert panels conducted and also to determine reliability, Cronbach’s Alpha coefficient performed.
A draft of 100 items questionnaire was developed and after evaluation of validity and reliability, final questionnaire included 46 items: 17 items for attitude, 13 items for subjective norms and 16 items for behavioral intention. For the final questionnaire average of content validity index was 0/92 and Cronbach’s Alpha coefficient was 0/85.
Based on the results of the current study the developed questionnaire is a valid and reliable instrument and it can be used to identify factors affecting nutritional behavior among people with metabolic syndrome based on the theory of reasoned action.