There are both pros and cons to standardized testing. The idea behind such testing is sound. The plan is for these tests to make sure that everyone has the same basic level of knowledge in a particular area before they move on. For example, it's a great plan for each ninth grader to enter the next year with the same knowledge base no matter what teacher or school they attended. Of course, it doesn't always work this way in practice. Often, too much emphasis is placed on the testing. Teacher begin to teach to the test rather than teaching the skills needed for the next level of education. Principles and other officials can become more concerned about test scores and how the school looks on paper instead of their students needs and actual learning.
There are benefits to standardized testing. For one thing, the testing has led to more of a discussion on the mismatch of funding in this country that has led to a huge gap in achievement. That is not enough though. The most useful estimator of test scores is zip code. Where you live shows your socioeconomic status and what school you attend. That is what really affects test scores.
Writing a truly good test is not easy or automatic. I agree in principle with the above post in the idea that a good test can be a helpful tool for assessment (and for instruction). The emphasis in standardized testing, however, has not been on the quality of the test. Instead the emphasis has been placed on the scores of students and the "scores" of schools and teachers.
This dynamic leads to a negative situation, in my opinion, where accountability in placed out of order. The test writers need to be held to higher standards so that students, teachers, and schools are being gauged according to a "true measure".
One other, separate point: Standardized testing is used too often. In a 10th grade classroom in California students spend one out of every nine days taking standardized testing. That is too much.
In my opinion, standardized tests should be 1) consolidated so that they are 2) given less often and they should be 3) much shorter for the students.
Some expectations have to be placed on the people scoring these tests. More essays will help to better assess a student's real skills.
If the standardized testing actually tests the right things, and if the test results are used in the right ways, then it is good. Of course, that is easier said than done. We have to be sure that the tests actually test things that are useful for students to know and the it is not clear that the tests should be "high stakes" or that they should happen as often as they now do.