3.1. Sample characteristics
One thousand six hundred and fifteen invited adults agreed to be followed-up for participating in a COVID-19 related survey, while 1,299 of them actually agreed to participate in this survey. Amongst these, 299 did not complete or provide valid responses to the questionnaire, and the remaining 1,000 provided valid responses to the survey experiment and other key questions in this study. The response rate was 62.0%. Among them, there were more people under 35 years in the sample than the Hong Kong population because the participant panel was established based on previous online surveys and more younger people were included as they usually spend more time using the internet than middle and old-age adults (