Two weeks ago I collected the evaluations and found them very useful.
My instructions were like this:
1) Must anonymous and typed
2) Should help me learn what I can do better and how
3) Should compliment me for good things (reinforements)
4) Express what you think personally, not what others say.
5) Evaluate yourself in terms of how much you learned so far
The forms were collected by a student and given to me. About 50% of
them were serious. I did comment on what I learned in general.