I guess the discussion of "evaluation" deserves a longer and more thoughtful note than I can ever find time to write, but in fact I HAVE thought about the matter for years. I never doubted the tests I took as a college student, nor the tests I gave when I taught at MIT. (Perhaps I should have...) But at the opposite extreme, it seems to me, are the standardized tests that so many people appear to believe in. An MIT calculus test tested a few sepecific things - like integrating by parts, say - which seemed important to nearly everyone, and were rather well defined, and were clear expectations.
That all seemed OK. But I watch what happens in schools in response to parental pressure on test scores, and it is usually a DISASTER! Whatever it is that the tests are thought to test becomes THE curriculum. That puts far too much emphasis on the things that are tested, and removes all interest and attention from anything that seems unlikely to be on the test.
But even that is not what's worst of all; the worst thing is that many teachers and supervisor believe that they are helping their students if they can raise the student's test scores, even though this may not involve teaching actual mathematics.
I have used elsewhere the actual example who wanted students to know that, in the numeral 2.10, you could omit the final zero (forget significant figures and all like that), whereas in the numeral 2.01 you could NOT omit the zero. The teacher told the students to think of the decimal point, and the final "1", as BOOK ENDS, that hold the 0 in place, whereas in 2.10 there not the necessary pair of bookends, so the zero can simply role away.
This (and MANY similar instances) may involve raising test scores,but without actually teaching any mathematics.
Often teachers feel compelled to spend LARGE AMOUNTS OF THEIR TIME ON THIS -- [sorry, my caps key got stuck[ ... to spend LARGE amounts of time on this sort of thing. this adds up to making mathematics incomprehensible.
I guess what I really feel is that we all need to ask WHY any particular test is used. In many cases, there is no really good reason. In other cases, where it might be important for a teacher to understand exactly how a student is thinking, most usual tests don't give you enough imformation. This is why my colleagues and I make so much use of videotaping students as they work on mathematical tasks - from which we often get some really valuable information about the thought processes of that individual student, and this is often exactly what we need if we are to help the student in the best possible way.
You can think of many GOOD reasons for some kind of assessment or evaluation or "testing" - and there certainly are many! -- but just doing it because it is presumed to be a "good thing" is NOT a good idea! And when testing IS a good idea, you need to be sure that the test is giving you the kind of information that is appropriate for that specific goal. "Routine" testing - the sort of thing parents and politicians seem so fond of - is very often NOT a good thing. In fact, it is often a harmful ritual, or a vote of no-confidence in teachers, who are presumed to be ready to do the wrong thing unless we keep testing their students. I prefer to look for teachers who are good enough to know what really is appropriate for each student, and who are usually harmfully limited when people who do not even know these students presume to dictate what the students really need.