Friday, October 12, 2018

Mike Andrews on Historical Patent Data

Mike Andrews is a postdoc at NBER, and I recently came across his PhD dissertation, Fuel of Interest and Fire of Genius: Essays on the Economic History of Innovation. He presents some interesting new results from historical patent records:

I already described the work in chapter 1 in my post on the NBER Summer Institute; in short, he compares U.S. counties that received new colleges in the period 1839-1954 with finalist sites that were not chosen for plausibly exogenous reasons. He finds that counties that received a college had 33% more patents per year, mostly due to increases in population rather than the colleges' graduates and faculty.

Chapter 2 looks at the effect of statewide alcohol bans on counties that previously set their own alcohol policies. Statewide prohibition reduced patents by 15% per year in previously wet counties relative to previously dry counties, and there is a larger decline for men than for women. Andrews suggests this decline is due to a disruption of information social interactions in saloons.

Chapter 3 matches 1870–1940 patents with census data and finds that patentees are consistently more likely to be older, white, male, and living in a state other than the one in which they were born. Establishment of a historically black college increased representation of black inventors, but the effect largely disappears after controlling for a county's black population, suggesting it is driven by concentration rather than the college itself. Extension of the franchise to women did not seem to increase the representation of women among inventors.

Finally, chapter 4 compares patent historical datasets. For those considering historical work with patent data, this is probably a good place to start. One should always be cautious about generalizing from the innovation institutions of a century ago to the ones that exist today—e.g., the effect of universities on the patent system has changed significantly in the past few decades—but it is still interesting to understand how patents worked in a particular historical context.

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