Procedure
RECRUITMENT, RECRUITMENT
Recruitment took place through paid-for online adverts with Facebook (including Instagram) and Google Search, limited to England-based IP addresses and targeted at Android devices. Online adverts were managed and optimized by a partner company called Nativve. Advert campaigns were run in two phases; from November 27, to December 12, 2020 and from January 5, to January 25, 2021. It was preplanned that if, after the first phase of recruitment or 35% of the target sample was reached, less than 45% of the sample were categorized as low socioeconomic status (SES) then over-sampling using advert targeting would be undertaken to increase low SES representation. Low SES was defined using the National Statistics Socio-Economic Classification,Clicking a study advert took individuals to the study website with study information including a downloadable participant information sheet. Those interested completed a screening survey and, if eligible, were asked to provide consent to participate using an e-signature. REDCaptcha, a captcha module available in REDCap,