Background
Web surveys have consistently lower response rates than all other survey modes [Systematic reviews and meta-analyses have examined different methods of increasing response rates in surveys of medical practitioner populations [Most studies used data generally more than 10 years old. As the use of email and the internet becomes more universal, including the more widespread use of electronic medical records, it is important to re-examine this issue. Nevertheless, for physician cohorts who are less familiar with the internet, mainly older physicians, there is uncertainty as to whether response rates would be different, and a risk that response rates will be lower with an email approach or online completion. Older people are less likely to respond to email than younger people [The aim of this research is to compare response rates between an email approach and a mailed approach within a national longitudinal survey of physicians. More specifically, we introduce an email approach in the second of three reminders sent to non-responding physicians. In the first ten annual waves of the survey, the main mailout and all three reminders were delivered by mail only. Our null hypothesis was that there would be no difference in the response rate when delivering the reminder by email or mail.