What do self-efficacy items measure? Examining the discriminant content validity of self-efficacy items

ObjectivesSelf-efficacy - an individual's judgement of their ability to successfully perform a behaviour - is commonly used to explain and predict behaviour. It is measured through self-report questionnaires. These scales require good content validity, that is must measure the full scope and content of the construct without contamination from similar constructs. This study uses a systematic, transparent quantitative method (discriminant content validation, DCV) to assess the content validity of a variety of self-efficacy items and qualitatively explores participant interpretations of these items. DesignA quantitative DCV and qualitative think-aloud study of self-efficacy item interpretation. MethodsParticipants (n=21) were presented with items designed to measure self-efficacy and related constructs following standard DCV methodology. Items were rated against construct definitions to determine whether they measured a particular construct (yes/no). Judges' confidence in each assessment was also assessed (%) and used to establish quantitative estimates of content validity for each item. A qualitative think-aloud study explored the judgements made in a subset of participants. Results8/8 self-efficacy items were found to measure self-efficacy; however, 2/8 of these also measured motivation. 6/8 items displayed discriminant content validity and thus can be considered pure' measures of self-efficacy. The think-aloud study indicated that item wording is a likely cause of item misinterpretation. ConclusionsSelf-efficacy items vary in terms of their content validity with only some of the items assessed providing pure' measures of the self-efficacy construct. Item wording should be considered during study design to avoid misinterpretation.