Nat. Med. 15, 230–231 (2009); published online 5 March 2009; corrected after print 6 April 2009

In the print version of this interview, the first response contained an unrelated excerpt from the previous month's Q & A. The text begins with “who could mobilize...” and ends with “...results and more results.” The error did not appear online in the HTML and PDF versions of the article.