From time to time the subjectpool administrator may want to clean the database from inactive participant profiles. ORSEE allows for that using the pending_profile_update_request flag. Here is the proposed procedure:

1. (Just to make sure:) Search for all participants, and use bulk action Set profile update request to set their flag to inactive.
2. Search for all active participants where last_activity was earlier than, say, 6 months ago.
3. Select all, and use bulk action Set profile update request to set the flag for these participant to active.
4. You will return to the same search result. Select all, and use bulk action Send bulk email to send these participants an email asking them to confirm their participation in the subject pool. They can confirm their participation by following the link to their profile edit page, which is automatically included in the footer of the bulk email. There, they checking and complete their data, and eventually confirm by saving their data. Give them a deadline, and tell them that they will be unsubscribed if they did not confirm by then.
5. Wait. You can monitor progress by searching for participants with pending_profile_update_request flag set to active. (The flag will automatically set to inactive when they edit and save their profile.)
6. Shortly before the deadline, you might want to send those who still have a pending_profile_update_request flag set to active a reminder email, using the bulk action Send bulk email' again.
7. Finally, search for participants with pending_profile_update_request flag set to active, and use the bulk action Set participant status to unsubscribe them from the database.

Another use case of this feature is when you introduce a new field in the participant profile form and want to make sure that all your active participants completed it (just approach all active participants rather than only those who have been inactive in the last 6 months), or when you want to move some subjects to a new sub-subject pool (which in turn may require different profile field data). An example of the latter case is when you want to ask students who soon leave university whether they would like to continue in an alumni pool (in this case you can use the field Upon accessing profile for update, set subject pool of participant to in the form for bulk action Set profile update request.