Diane Ravitch said:

It’s totally inappropriate to compare opting out of testing to opting out of immunization. One has a scientific basis, the other has none. The tests that kids take today have nothing to do with the tests that we took when we were kids. When we were kids, we took an hour test to see how we did in reading, an hour test to see how we did in math. Children today in third grade are taking eight hours of testing. They’re spending more time taking tests than people taking the bar exam.

Now, when we talk about the results of the test, they come back four to six months later. The kids already have a different teacher. And all they get is a score and a ranking. The teachers can’t see the item analysis. They can’t see what the kids got wrong. They’re getting no instructional gain, no possibility of improvement for the kids, because there’s no value to the test. They have no diagnostic value.

[It’s as] if you go to a doctor and you say, ‘I have a pain,’ and the doctor says, ‘I’ll get back to you in six months,’ and he gets back to you and tells you how you compare to everyone else in the state, but he doesn’t have any medicine for you.

via http://www.washingtonpost.com/blogs/answer-sheet/wp/2015/04/16/why-the-debate-between-diane-ravitch-and-merryl-tisch-was-remarkable