An Even Clearer Portrait of Bias in Observational Studies? Erratum

In the July 2015 issue of Epidemiology in the article by Davies, “An Even Clearer Portrait of Bias in Observational Studies?”, the Creative Commons License was cited incorrectly. The correct license is: This is an open access distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.