RCT: Paper survey and push-to-web survey
MAY
The paper and push-to-web surveys were both cross-sectional population-based postal surveys carried out in England. The Office for National Statistics (ONS) identified 16,050 women from birth registration records in England and randomised these women to either the paper survey or the push-to-web survey. Stratified block randomisation of women based on region of residence in England was applied in a ratio of 1:1 and sequence generation was determined by ONS using Microsoft Access Visual Basic for Applications (VBA) code. Blinding and allocation concealment were not possible. The paper and push-to-web surveys each included a random sample of 8,025 postpartum women, which was representative of the target population: all women aged 16 years or older who had given birth in England during a two-week period in May 2020, and who were living in England at the time the birth was registered. Both the paper and push-to-web surveys involved contacting women by post with up to three mailings: an initial invitation (in November 2020), a reminder after 2–3 weeks (in December 2020), and a final reminder after a further 4–5 weeks (in January 2021).In the paper survey, women received an invitation letter, participant information sheet, multi-language information sheet, a paper questionnaire and a reply-paid envelope with each mailing. The invitation letter in the paper survey also included details of how women could take part online using a web address or by scanning a QR code, if this mode of response was preferred. In the push-to-web survey, women received an invitation letter, participant information sheet and multi-language information sheet but the inclusion of a paper questionnaire and reply-paid envelope were withheld until the third (and final) mailing. Again, details of how to access the online survey were provided in the invitation letter, along with details of how to obtain a paper questionnaire, if this mode of response was preferred. Responses in the paper survey and the push-to-web survey were accepted until the end of March 2021 and all respondents were offered the option to receive a £5 shopping voucher by providing their email address, either on paper or online.