Increasing student participation in online evaluations

Over the last few years, OCOM has seen a significant decline in the evaluation response from students. We are trying to figure out a way to incentives evaluation completion (beyond just locking grades). I am curious if it would be possible to add a function in the current evaluation system that when a student clicks "Submit" on their evaluation for a course that it would take them to a link (perhaps survey monkey or the like) where they can enter their name in a drawing of some sort. This would allow anonymity to remain, it would just take the student to a page with the link where they can choose to enter their name for a drawing in a separate system.