John Cassidy complicates the study Leonhardt touts:
Yes, good teaching is important. But the key policy issue is raising average teaching standards throughout the education system, not simply seeking out and rewarding exceptional kindergartens. In affluent areas of New York City, parents’ efforts to capture every possible educational advantage for their young children have already reached absurd levels. If this new research is accepted as gospel, I can already see admissions officers at snooty private schools waving it in the air and saying to parents: Look, I told you our $30,000 fees were justified. Where else can you find a kindergarten teacher with a Princeton Ph.D. in Victorian literature?”