Participants
The research was conducted within the context of the Medicine in Australia: Balancing Employment and Life (MABEL) survey. This was a longitudinal panel survey of all medical practitioners in Australia, collecting 11 annual waves of data from around 9,000 to 10,000 physicians per wave [The sample frame for MABEL is the Medical Directory of Australia, a national database of doctors held by the Australasian Medical Publishing Company (AMPCo). We use participants from Wave 11, administered between August 2018 and April 2019. Doctors were excluded if they had previously requested to withdraw from the MABEL survey, or who were known to be deceased. Junior doctors were excluded since in 2016 we conducted a small experiment that supported the use of an email approach for junior doctors and this was adopted in subsequent waves for this group only [The invitation included a mailed letter that contained unique log in details for online completion to enable longitudinal tracking, as well as a paper copy of the survey which included a unique username printed on the cover. Respondents could choose the mode of completion. The first reminder used a mailed paper letter containing instructions for online completion but no paper survey. The second reminder used a mailed letter with instructions for online completion and included a paper copy of the survey. The third reminder included only a mailed paper letter with instructions for online completion.