Sandhya, Oftentimes, many instructors are faced with a pre-established grading system. Evaluating student performance is different from creating a grading system. We can evaluate students every - even througout the day. I "check for understanding" continuously when I have a lecture segment. I'll go just so far, then ramdomly call on a student to summarize. If correct, great, and I move on. If not, I'll call on another student at random. If after three students there is not clear understanding, I go back and review the material. This is also a way to keep students engaged because they never know which name is going to be called. Barry Westling