Development of the Adelaide Driving Self-Efficacy Scale

Objective: To describe the development of the Adelaide Driving Self-Efficacy Scale (ADSES) and to report on its reliability and validity. Methods: A set of 12 driving behaviours, developed through literature review, clinical experience and expert review, were rated for self-efficacy using a Likert scale. Internal consistency was investigated using a Cronbach's alpha coefficient and construct validity by comparing ADSES scores of stroke and non-stroke drivers. Criterion-related validity was examined by comparing ADSES scores with the result on a standardized on-road assessment. Setting: A rehabilitation hospital in Adelaide, South Australia. Participants: Staff from the hospital and stroke patients from the rehabilitation unit. Data from a non-stroke sample (n = 79) and stroke patients (n = 81) were used to test internal consistency and construct validity. A separate group of 45 people recommended for a driving assessment, of whom 34 were stroke patients, were used to test criterion validity. Results: Cronbach's alpha coefficient was 0.98, indicating high internal consistency. The non-stroke and stroke groups showed significant differences in ADSES scores (t(158) = 5.5, P < 0.05), demonstrating construct validity. Differences in ADSES scores for those participants who passed or failed the on-road assessment were significant for both the entire driving assessment group (t(43) = 3.2, P < 0.05) and the stroke subgroup (t(43) = 3.2, P < 0.05), indicating criterion validity. Conclusion: The ADSES has demonstrated internal consistency and construct validity with the stroke and non-stroke population. The scale demonstrated criterion validity in its relationship with outcome of an on-road driving assessment. It appears to be a reliable and valid measure of driving self-efficacy.