In his review of Does Measurement Measure Up? How Numbers Reveal and Conceal the Truth by John M. Henshaw (Nature 442, 357, 2006), David Colquhoun criticized the methods of ranking the quality of teaching at UK universities. In fact, the Quality Assurance Agency for Higher Education (QAA) stopped its assessment of the teaching quality of individual subjects, resulting in a graded numerical profile, in 2001, and discourages others from using its judgements in league tables.

In a review of Reconceiving the Gene: Seymour Benzer's Adventures in Phage Genetics by Frederick Lawrence Holmes (Nature 443, 509, 2006), we omitted to mention that the book was completed and edited by William C. Summers. We apologize to Professor Summers for this oversight.