One of the biggest struggles in teaching is knowing if you are being effective in your ability to create true learning in students.
Often it is considered a standard practice to evaluate effectiveness in teaching on test scores and overall achievement in a program. However many studies have found that basing teaching effectiveness on test scores has many flaws and is an ineffective tool for measuring classroom performance of both the students and the instructor.
If you as a teacher/instructor/professor are truly interested and motivated to cause real learning in your students then you must implement some form of feedback mechanism from the students to gauge their engagement on a timescale that is smaller than a term of school. Taking exit surveys at the end of a course is too late you can no longer help those students, and due to the variability of cohorts and classes the feedback from one group may not apply or be a hinderance to the next group of students.