Getting cited: does open access help?

We reexamine the widely held belief that free availability of scientific articles increases the number of citations they receive. Since open access is relatively more attractive to authors of higher quality papers, regressing citations on open access and other controls yields upward-biased estimates. Using an instrumental variable approach, we find no significant effect of open access. Instead, self-selection of higher quality articles into open access explains at least part of the observed open access citation advantage.