Does Copyright Affect Reuse? Evidence from Google Books and Wikipedia

While digitization has greatly increased the reuse of knowledge, this study shows how these benefits might be mitigated by copyright restrictions. I use the digitization of in-copyright and out-of-copyright issues of Baseball Digest magazine by Google Books to measure the impact of copyright on knowledge reuse in Wikipedia. I exploit a feature of the 1909 Copyright Act whereby material published before 1964 has lapsed into the public domain, allowing for the causal estimation of the impact of copyright across this sharp cutoff. I find that, while digitization encourages knowledge reuse, copyright restrictions reduce citations to copyrighted issues of Baseball Digest by up to 135% and affect readership by reducing traffic to affected pages by 20%. These impacts are highly uneven: copyright hurts the reuse of images rather than text and affects Wikipedia pages for less-popular players greater than more-popular ones.