I didn't read that as saying that testing can predict (outstanding) success. I read it as saying that testing can detect (outstanding) failure. If a student do

I didn't read that as saying that testing can predict (outstanding) success. I read it as saying that testing can detect (outstanding) failure. If a student does at least moderately well on standardized tests, there's a decent chance they'll do at least moderately well later in life. If most of a teacher's students flunk completely on the standardized tests, the teacher probably isn't doing a very good job.