Examples of syllabus language to address student evaluations:

• At the end of this course, you will be asked to complete an evaluation of this course.  It will be a chance to reflect on what we have accomplished and to propose ways the course might be modified for your peers in the future.  
• All learning—and indeed teaching—is self-reflexive and dynamic. Consequently, as this course evolves, in addition to more informal moments for feedback (such as office hours, where I hope you’ll all stop by on occasion), we have three brief surveys.  The first is a pre-class form which lets you tell me a bit about your expectations for the course, just as this syllabus tells you about mine.  Second, roughly midterm, we will have another survey of a few open-ended questions that ask you to consider how the class is going.  Finally, in the last week of class, we will have the official evaluation, in which you will answer questions developed both by the college and myself to help assess how the class went well and where it can be improved.
• Near the end of the semester, you will be asked to complete an online course evaluation form.  Your feedback on the course is extremely valuable to me.  I read my students’ comments carefully and use them to improve the course the next time I teach it.
  [Optional:] When the time comes, please let me know which aspects of the course helped you learn—and which aspects might be modified to help future students learn more effectively.
  [Optional:] Please note that the course evaluations are anonymous and that I won’t see the results until after the grades for the course are submitted, allowing you to provide honest and constructive feedback.
  [Optional:] And if you have feedback to offer before the end of the semester, please let me know.