Owing to an editorial error, the titles in the affiliations of Andreas Schädel and Julian Wucherpfennig in the article by Cederman et al. (2015) in the May 2015 issue of American Political Science Review are incorrect. The correct affiliations are as follows:
Andreas Schädel is PhD candidate at ETH Zürich, Haldeneggsteig 4, 8092 Zürich, Switzerland (email@example.com).
Julian Wucherpfennig is Lecturer in International Security at University College London, 29/31 Tavistock Square, London, WC1H 9QU, United Kingdom (firstname.lastname@example.org).
We regret the error.