Do I have to complete the additional activities?

No — your participation is entirely voluntary. You can choose to complete just the questionnaire and opt out of the additional activities. Or you can choose to do the activities and opt out of the questionnaire. If you do decide to complete these activities, you can stop at any point if you no longer wish to continue. Your decision will not affect your ongoing participation in NCDS and any contribution you can make to this survey will still be really valuable.