Do I have to complete the problem-solving tasks?

No — your participation is entirely voluntary. You can choose to complete just the questionnaire and opt out of the problem-solving tasks. Or you can choose to do the tasks and opt out of the questionnaire. If you do decide to complete the tasks, 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.