is there any validity in academic testing?

Now that I'm getting ready to apply for jobs and graduate programs, I've have to come into contact with my transcript more than I would have liked to. Over the past four years, I've had my share of abysmal grades. And I'm not being dramatic, some semesters have been just as atrocious as you can get. When I think back to the courses in which I had received such poor grades, I realize that the classes were based almost solely on exam grades. You do poorly on an exam or two, and you don't really have an opportunity to help yourself. Is that really fair? Grades, after all, are supposed to be indications of how well a student is understanding the course material, not punishments for inadequate or misguided study habits.

I get that "intelligence" or "knowledge of a subject" needs to be operationalized somehow in order to make comparisons. While an exam is a way to numerically gauge how much a student has retained about a subject, it almost never truly displays their understanding of it. When you see a student cramming for an exam - whether it be biochemistry or history - you see them hunched over a notebook full of facts and figures, attempting to jam their head full with as much as possible, with the hope that come exam time, they will be able to regurgitate enough to form cohesive answers.

If exams really did a good job of assessing knowledge of a subject, why do students dread cumulative exams so much? If we had truly gained an understanding of material we were previously tested on, we would prefer a cumulative exam, which would allow us to integrate across material of multiple exams. If professors are going to really use testing to assess a student's understanding of material, they should make exams cumulative, because to me, mastery of a subject requires integration, rather than being able to report on bits and pieces of material.

While standardized testing has been continually lambasted for being an inadequate measure of how prepared a student is for college or graduate schools, there is not much more of an option. However, once you're at school, professors have an entire semester to gauge their students' understanding of the course material. By spreading the grade out over a variety of assignments, some of which are subjectively graded by the professor, not only will students who consider themselves "bad test-takers" feel that they have equal opportunity to do "well" in the class, but there will be much less extrinsic motivation and would most likely spur students' interests in the course material itself. Isn't that what college courses are supposed to be about anyway? Spending four years consistently worried about grading and cramming could potentially be a big precursor for giving students a propensity to dislike fields they would otherwise be interested in.

It would be interesting to perform some kind of meta-analysis comparing students who take classes in which grades are overwhelmingly based off of exam grades and those who receive grades more based off of presentations/papers/integrative assignments. Not only would it be cool to see how GPAs differ, but to see which students pursue careers directly correlated with what they studied in college. How satisfied were they with their collegiate experiences? How do they perform on other, non-academic based, integrative and/or memory tasks? Are there really such people as "bad test-takers"?