This dissertation, which consists of four chapters, uses historical patent data to understand invention in the United States. The first chapter studies how institutions of higher education affect invention. The second chapter seeks to understand the importance of informal social interactions for the creation of new ideas. The third chapter answers the question of what types of individuals are most likely to become inventors. The fourth chapter discusses various historical patent datasets in detail.
In Chapter 1, I exploit historical natural experiments to identify the causal effect of the establishment of new colleges on local patenting. Using losing finalist counties that did not receive a new college as counterfactuals, I find that the establishment of a new college caused 33% more patents per year in college counties relative to the losing finalists. To understand the role of a college education in driving patenting in college towns, I use a novel dataset of graduates from college yearbooks and find that a college's graduates and faculty account for a very small share of the patents granted in that college's county. Changes in county population account for 45-65% of the increase in patenting in college counties.
In Chapter 2, I exploit a different historical policy to understand the importance of informal social interactions for invention. More specifically, I examine the effects of state-level alcohol prohibition in the U.S. Prior to the enactment of statewide alcohol laws, each county determined its own alcohol policies. Thus, statewide prohibition differentially treated counties depending on whether they were wet or dry prior to statewide adoption. The imposition of statewide prohibition reduces the number of patents by 15% per year in previously wet counties relative to previously dry counties. The effect is largest in the first three years after the imposition of prohibition and diminishes thereafter. Consistent with this decrease being driven by a disruption of informal social interactions, the patenting rate for men decreased more than that for women in previously wet counties.
In Chapter 3, my coauthors and I match the Annual Reports of the Commissioner of Patents from 1870 to 1940 to the corresponding U.S. Federal Population Censuses. This matching procedure provides a rich set of demographic information on a comprehensive set of inventors, allowing us to answer the fundamental question of who invents. We first document that patentees are more likely to be older, white, male and to be living in a state other than the one in which they were born. These patterns are very persistent over space and time. We then attempt to identify correlates of the demographics of patentees focusing on county-level economic and demographic characteristics. Beyond the most obvious, such as the fraction of a particular demographic group in that county, very little explains differences in the demographics of inventors across counties.
In Chapter 4, I compare the strengths and weaknesses of four historical patent datasets and consider the suitability of each for use in economic research. I describe in detail differences in terms of the type and reliability of included information and potential sample selection issues. I show that while there are differences across datasets, overall they paint a remarkably consistent picture of invention in U.S. history.