Background: Effective skin self-examination can enable early diagnosis and treatment of skin cancer, which otherwise could result in significant morbidity and mortality. We compare the effects of watching a DVD and reading printed materials on self skin examination. Methods: Longitudinal data from the Randomized Skin Awareness Trial were analysed (n=984). The control group were provided with written materials describing how to conduct effective skin self-examination. The intervention group received additional instruction from a DVD. It was hypothesized that self skin examination may be confounded by unobserved variables. A recursive model was specified to control for this potential source of bias. Results: At six months only watching the DVD had a statistically significant effect on diagnosed skin cancer. By 12 months both interventions were statistically significant; reading the printed materials was 63% as effective as watching the DVD. Conclusion: Watching a DVD was associated with the largest increase in diagnosed skin cancer. However, reading written materials was also associated with an increase in diagnosed skin cancer. Both visual and written communication should be considered when designing an effective skin self-examination programme.