| Abstract: |
While the potential for intellectual property rights to inhibit the diffusion
of scientific knowledge is at the heart of several contemporary policy
debates, evidence for the %u201Canti-commons effect%u201D has been anecdotal.
A central issue in this debate is how intellectual property rights over a
given piece of knowledge affects the propensity of future researchers to build
upon that knowledge in their own scientific research activities. This article
frames this debate around the concept of dual knowledge, in which a single
discovery may contribute to both scientific research and useful commercial
applications. A key implication of dual knowledge is that it may be
simultaneously instantiated as a scientific research article and as a patent.
Such patent-paper pairs are at the heart of our empirical strategy. We exploit
the fact that patents are granted with a substantial lag, often many years
after the knowledge is initially disclosed through paper publication. The
knowledge associated with a patent paper pair therefore diffuses within two
distinct intellectual property environments %u2013 one associated with the
pre-grant period and another after formal IP rights are granted. Relative to
the expected citation pattern for publications with a given quality level,
anticommons theory predicts that the citation rate to a scientific publication
should fall after formal IP rights associated with that publication are
granted. Employing a differences-indifferences estimator for 169 patent-paper
pairs (and including a control group of publications from the same journal for
which no patent is granted), we find evidence for a modest anti-commons effect
(the citation rate after the patent grant declines by between 9 and 17%). This
decline becomes more pronounced with the number of years elapsed since the
date of the patent grant, and is particularly salient for articles authored by
researchers with public sector affiliations. |