Question

Do grades reflect students who is trying hard in the class?

Answer 1

Not necessarily. Grades can be considered a measure of a result, it would depends a lot of the result you are measuring. For example, if you measure the behaviour of interest in class, the student that is trying hard in class would score well. But it also can happen that when that student face a test get blocked and stressed and do not score that well. Grades will always depend on what is measured, and currently those measures will be strictly connected with the beliefs of the teacher and his understanding of the most effective way of teaching.