FACULTY AND RESEARCH

Does online access boost citations to an economics article? The answer has implications for a range of issues from the sustainability of open-access journals (which shift journal fees from subscribers to authors) to the nature of economists’ citing behavior, to the impact and diffusion of new digital technologies. Using detailed panel data on citations to the universe of articles published in 100 of the top economics and business journals, we exploit exogenous variation in the timing of the online availability of print content to isolate the causal effect of online access from spurious selection effects plaguing previous studies. Controlling for quality with increasingly rich fixed-effects specifications reduces the measured effect of online access from the high levels (as much as 500%) found in previous studies to near zero. This aggregate zero effect masks substantial heterogeneity across platforms: JSTOR availability has a significant impact, boosting citations an average of 10%, whereas no impact is observed for Elsevier's Science Direct platform. The citation boost is uniform across the distribution of articles—from rarely cited articles in the “long tail” to “superstars”. We explore further sources of heterogeneity in the citing author’s geographic location and institutional affiliation, and the rank of the cited journal.