It's important to have a deadline and to ensure participants are aware of it. We recommend that you include the deadline in all of your email communications, including the invitations and reminders you send in Spidergap.
You may wish to communicate a 'soft deadline'. A soft deadline is a deadline a few days before the real 'hard deadline'. By communicating the earlier deadline, you can then give latecomers a few extra days to submit their feedback, which can help to improve response rates.
When the real deadline has passed, you can close the assessments to prevent any further responses.
Currently, it isn't possible to schedule the reminders and closing of assessments in Spidergap. Instead, we recommend that you add events to your own calendars that remind you when to take these actions.