There are a few academicians who oppose giving exams in college courses. Their argument is that students should learn for the love of learning and that fear of exams creates an adverse, threatening atmosphere. I agree that learning can be intrinsic ally rewarding, but I also believe that there are several cogent reasons for giving exams in college.
The most obvious function of an exam is that of assessment. I earlier pointed out that most college courses are based on a mastery concept and an exam is most efficient way for the professor to find out whether your knowledge of the subject satisfies the criterion level for that course. This assessment function is also important to you because it provides feedback that may influence your future plans. For example, your career goals could be changed if you do well in a subject that is new to you, or poorly in a subject that is critical to some professions. At the least, feedback from exams is important in deciding whether you are prepared for more advanced work in a discipline. Even if the news is not always good, it is best to know your strengths and weaknesses.
Another important function of exams is that of a stimulator/motivator. What I mean is that almost everyone needs a clear signal that it is time to shift attention from learning to memory, and also some added motivation to do the additional work. You may know that organizing and integrating facts into a coherent body of knowledge is important, but it is easy to convince yourself that you know you know the material, so you don't need to spend the time preparing to prove it to others. But in fact, learning something now is futile unless you can remember it in the future, and hence the incentive to prepare for an exam helps insure that you complete the learning-memory cycle. To me, the most important reason for giving exams is to reward good students for having mastered the subject. Many students think that the teacher's goal is to detect students goofing off and to give obscure questions that most students will fail. There may be a few teachers like that, but most of us want you to learn, want you to do well, and want to give you a good grade as recognition for your accomplishment. You might prefer some other prize, but quality grades are the only tangible tokens that college teachers have to reward students who deserve them. Most college professors would gladly give quality grades to every student in a class provided every student showed a high level of achievement. That is very unlikely, however, at least in typical freshman/sophomore courses. Now if good grades are to have their intended reward value for good students, poor students have to receive poor grades. A prize that all students receive regardless of their performance is not much of a prize at all. Students who earn low grades have to receive low grades if high grades are to function as rewards for students who earn high grades. Hence, a meaningful grading system will lead to a distribution of grades that corresponds to the distribution of student performance levels.