(Molecular Cell 67, 348–354; July 20, 2017)In our manuscript, we erroneously labeled sequences that were downloaded using the Dharmacon CRISPR RNA Configurator website as being selected with the Edit-R algorithm. These sequences were not selected by the Edit-R algorithm, nor were any Dharmacon products used in this manuscript. As a result, we are unable to draw conclusions regarding the efficacy of the Edit-R algorithm relative to the CRoatan algorithm. We apologize for any confusion this may have caused.