Be able to report on tasks marked as completed

It would be great to be able to run reports on a specific task and see who has marked this as complete and for those who it is still outstanding for. We currently have an annual reminder process whereby once a year, we ask staff to review their personal details. In this process, a task is triggered to staff to mark as complete, and it would be helpful to know who hasn't marked this as complete so we can give them a chase etc.