Review of the psychometric properties of the Diabetes Self-Efficacy Scale: Australian longitudinal study.

The current paper presents the findings from the reliability and validity testing of an 18-item Diabetes Self-efficacy Scale derived from the 28-item Insulin Management Diabetes Self-efficacy Scale. Testing in the Australian context occurred at three points over 9 months. Diabetes self-efficacy is defined as the individual's judgement of confidence to carry out tasks specific to diabetes management. Data were obtained from an Australian metropolitan sample of adult, English speaking men and women with diabetes (N = 226). Participants were insulin-using and non-insulin-using. Factor analysis indicated five subscales. The data support the construct validity and reliability of the 18-item scale in terms of stability, internal consistency and item-total correlation matrices. This study provides consistent evidence that the Diabetes Self-efficacy Scale is a valid and reliable measure over time when the individual's efficacy beliefs are changing. Hence this instrument should be a useful outcome measure for educational diabetes related interventions.