Test–Retest Reliability of the Susceptibility to Driver Distraction Questionnaire

Abstract

The Susceptibility to Driver Distraction Questionnaire (SDDQ) investigates voluntary and involuntary factors associated with driver distraction. The questionnaire consists of 39 items in six subscales: (a) self-reported distraction engagement, (b) attitudes toward distractions, (c) perceived control of driving while engaged in distractions, (d) injunctive social norms associated with distraction engagement, (e) descriptive social norms associated with distraction engagement, and (f) susceptibility to involuntary distractions. A sample of 43 adults, ages 25 to 39 years, was used to assess the test–retest reliability of the SDDQ. The mean time between test and retest conditions was approximately 20 days. For sub-scale averages, intraclass correlation (ICC) statistics were used to assess test–retest reliability; weighted kappa statistics were used to assess individual items. The ICC results suggest good to excellent test–retest reliability for subscales of self-reported distraction engagement, attitudes toward distractions, and descriptive social norms. Perceived control of driving while engaged in distractions had fair test–retest reliability, and the injunctive norms and susceptibility to involuntary distraction subscales had poor test–retest reliabilities. The latter two subscales may have to be redesigned; this paper provides relevant suggestions for revision in the discussion of the results. As an additional preliminary analysis, data from a sample of 10 additional participants were used to investigate the consistency of responses across longer periods of time. The mean time between test–retest conditions in this sample was approximately 8 months. In general, the findings were similar to those in the main sample. Overall, the SDDQ appears to have good test–retest reliability. A larger sample is recommended for further validation of these results, in particular across long test–retest periods.