How to create incentive for students to take surveys?
I think that giving some small course credit for a survey like that can be a good idea. Taking the IRB protocols as a model, you might give course credit for the survey, and also some alternate assignment for a student who has some point of principle that makes them not want to disclose personal info like that. Then you've really covered your bases.

In my own case, I give a study survey like that after the first exam. Since this happens to be in sequence and in the same format as three earlier quizzes, I think many students assume that it's for credit and complete it without me saying one way or the other (it's not, and has a different title, but it serendipitously works in my favor that way).