Nat. Methods 10, 1169–1176 (2013); published online 26 November 2013; corrected after print 27 January 2014

In the version of this article initially published, the formula describing the connection specificity index (CSI) in Box 2 was incorrect. The denominator in the fraction of the CSI equation originally read “ny”; the correct denominator is “# of X-type nodes in the network.” The error has been corrected in the HTML and PDF versions of the article.