Survey development and administration
Two trial statisticians based at the Centre for Statistics in Medicine (CSM) piloted the surveys for authors of protocol publications and provided feedback on functionality and design. Only surveys one and three were piloted as they contained the same questions as surveys two and four but with additional questions at the start.Personalised emails (including the corresponding author’s name, the title of their publication, and a unique survey URL link) were sent to each corresponding author by KM. Where automated email responses were received that provided an alternative email the email was forwarded on. Surveys were open from the 17th of January until the 14th of February 2022 and were designed to take between 5 and 10 min to complete. Non-respondents were sent a reminder email two weeks after the initial contact email, and all respondents were invited to enter a prize draw to win a £50 One4All voucher upon survey completion.