One of the universities I work for asked professors to announce the online evals in class. They even gave us a template to work from. See my version below.
The point to be customized by individual faculty:
Just as I have provided all of you with feedback throughout the course, I am now requesting your feedback for me. It’s time for the student evaluations of teaching and I’m asking all of you to fill out the online survey. This means a lot to me as your professor because… I would really like to gauge all of your thoughts about this course and about my effectiveness as an instructor. I will use the information to improve my course the next time I teach it.
My customized version
My job is to give you feedback so you can learn. Now it’s your turn. So, I’m on my knees begging you – wait, that’s a cliché – I’m urging you to do this evaluation. Hardly any of my students did it last time and they all hated me. Not really. But, apparently, whoever wrote this is under the impression that students will act on something because it “means a lot” to their professors. Right. It is true that I take all those chili peppers --- I mean feedback -- to heart. I really try not to sound like “a crazy person talking to herself in a rant for an hour and a half.” Keep in mind that the department folks look at evaluations when choosing from growing stable of adjunct journalism professors. We wait each semester for a class like the men who gather on suburban corners at dawn hoping for a day of landscaping work. So, here’s your chance to boost or bust me. Go at it but make sure to use active voice.