In the last four years McKinsey and Company have produced two highly influential reports on how to improve school systems. The first McKinsey report "How the world's best-performing school systems come out on top" has since its publication in 2007 been used to justify change in educational policy and practice in England and many other countries. The second "How the world's most improved school systems keep getting better," released in late 2010, is a more substantial tome which is likely to have an even greater impact. This article subjects both reports to a close examination and finds them deficient in 10 respects. The detailed critique is preceded by a few general remarks about their reception, influence and main arguments. (Contains 4 figures and 13 notes.)