Rather than rely on my anecdotal evidence, a new NBER paper examines the role of Patent Depository Libraries as evidence of patent disclosure. Jeffrey Furman (Boston U. Strategy & Policy Dept), Markus Nagler, and Martin Watzinger (both of Ludwig Maximillian U. in Munich) have posted Disclosure and Subsequent Innovation: Evidence from the Patent Depository Library Program to NBER's website (sorry, it's a paywall unless you've got .gov or .edu rights). The abstract is here:
How important is information disclosure through patents for subsequent innovation? Although disclosure is regarded as essential to the functioning of the patent system, legal scholars have expressed considerable skepticism about its value in practice. To adjudicate this issue, we examine the expansion of the USPTO Patent and Trademark Depository Library system between 1975 to 1997. Whereas the exclusion rights associated with patents are national in scope, the opening of these patent libraries during the pre-Internet era yielded regional variation in the costs to access the technical information (prior art) disclosed in patent documents. We find that after a patent library opens, local patenting increases by 17% relative to control regions that have Federal Depository Libraries. A number of additional analyses suggest that the disclosure of technical information in the patent documents is the mechanism underlying this boost in patenting: the response to patent libraries is significant and of important magnitude among young companies, library opening induces local inventors to cite more geographically distant and more technologically diverse prior art, and the library boost ceases to be present after the introduction of the Internet. We find that library opening is also associated with an increase in local business formation and job creation, which suggests that the impact of libraries is not limited to patenting outcomes. Taken together, our analyses provide evidence that the information disclosed in patent prior art plays an important role in supporting cumulative innovation.The crux of the study is the match to other, similar areas with Federal Depository (but not patent) Libraries. The authors acknowledge that the opening of a patent library might well be a leading indicator of expected future patenting, but the authors discount this by arguing that the Patent Libraries would have had to somehow predict the exact year of increased patenting, and then apply in advance of that date and get approved just in time. The odds of this seem low, especially when the results are localized to within 15 miles of the library (and no further).
The first core finding, that patenting increased, is ambiguous normatively. The authors discuss enhanced innovation, but equally likely alternatives are that people just got excited about patenting or that innovation already occurring was more easily patented. That said, they find the same quality, which implies that the patenting wasn't simply frivolous.
The second finding is more important: that the types of citations and disclosures changed (and that those changes disappeared when patents were more readily available on the Internet). This finding implies that somebody was reading these patents. The question is who. A followup study looking at how the makeup of inventorship changed would be interesting. Were the additional grants solo inventors or large companies? Who used these libraries?
Even without answering this question, this study was both useful and interesting, as well as a bit nostalgic.