In this article, we document that the Organisation for Economic Co-operation and Development (OECD) and the Conference Board’s Total Economy Database (TED) have substantially revised their measures of hours worked over time. Relying on the data used by Rogerson (2006) and Ohanian et al. (2008), we find that, for 2003, hours worked per person in Europe is 18 percent lower than hours worked in the United States. Using the 2016 releases of the same data for 2003 yields a gap that is 40 percent smaller—that is, only 11 percent lower. Using labor force survey data, which are less subject to data revisions, we find a Europe-U.S. hours gap of –19 percent.