Results
Of the 1,918 people who consented to take part in the study, 1,654 were randomised to 1 of the 4 study arms. Of those, 1,439 participants (87%) provided complete responses that were deemed valid due to completion time (not too fast [>210 s control arm, >330 s Questions arm, >480 s Video arm, >570 s Questions and Video arm] or too slow [<2 h]) and were included in the final analysis. These time cutoffs were chosen post hoc by determining an absolute minimum or maximum time for engagement with the content of the survey, due to concerns about the quality of fast or slow responses (Participant flow diagram.At 2-wk follow-up, 1,254 participants (87.1% of analysis sample; 75.8% of initially randomized sample) completed the questionnaire. Of these, 16 began but did not complete the survey, 44 had invalid response speeds, and 54 had partially incomplete data (i.e., did not respond to all follow-up questions).