Immigrants Played an Outsize Role in America’s Age of Innovation
America has always been “a nation of immigrants” to quote the title of John F. Kennedy’s famous book. Yet the role of immigrants in U.S. competitiveness has become increasingly contentious, especially in light of the recent presidential election. Our research attempts to shed light on this debate, by focusing on the history of immigrants as technological innovators.
To study the role of migrant inventors in U.S. innovation, we linked the birthplace of millions of individuals from Federal Censuses between 1880 and 1940 to millions of inventors from patent records. Using labor income information in the 1940 Census, we further examined how immigrant and domestic-born inventors were compensated.
Large scale data compiled from U.S. patent and Census records allows us to move beyond the anecdotes of successful immigrant inventors, of which there are many. For example, Alexander Graham Bell, a key figure in the invention of the telephone, was born in Scotland; the Swedish inventor David Lindquist played a major role in the development of the electric elevator; and Herman Frasch, a German-born chemist, worked in Philadelphia and Cleveland on mineral exploration and extraction, which can be linked to present-day fracking.
Our study shows that immigrants accounted for 19.6% of all inventors between 1880 and 1940. Today, that share is approximately 30%. The chart below shows the share in each state of inventors who were born abroad. Immigrant inventors were heavily concentrated in U.S. “rust-belt” states, which were some of the most productive areas during the late nineteenth and early twentieth centuries. They were noticeably absent from southern states, where they may have faced either fewer economic opportunities, or cultural barriers to assimilation.
We also looked at the technology areas in which immigrant inventors were active. The largest share of immigrants were involved in developing medical technology inventions, such as surgical sutures. But medical technology accounted for just 1% of all U.S. patents. In areas that had a much larger effect on the U.S. economy at this time – specifically electricity and chemicals, which accounted for 13.9% and 12.6% of all U.S. patents respectively – immigrants were also strongly represented. Migrant influence was widespread, with migrant inventors accounting for at least 16% of patents in every technology area. The majority of immigrant inventors originated from European countries, with Germans playing a particularly prominent role.
To examine the relationship between immigrant inventors and U.S. technological development over the long-run, we constructed a measure that we call foreign-born expertise. In effect, this measure captures the extent to which inventive expertise in a particular technology area may have been transmitted by the movement of foreign inventors to the United States.
Areas of technology with higher levels of foreign-born expertise experienced much faster patent growth between 1940 and 2000 than otherwise comparable technology areas, in terms of both the number of patents and a citation-adjusted measure of patent “quality”. That relationship isn’t necessarily causal, however our results provide suggestive evidence that immigrant inventors played a key role in the development of America’s technology leadership.
Migrant inventors may have an outsized influence on innovation for two primary reasons. First, immigrant inventors like Nikola Tesla, who was born into a Serbian family, develop important ideas in their own right. Additionally, their insights may augment the skills of domestic inventors through collaboration. For example, in the 1940s Canadian immigrant James Hillier developed the first commercially viable electron microscope at Radio Corporation of America alongside Ladislaus Marton, a Belgian inventor, Vladimir Zworykin, a Russian inventor, and U.S.-born engineers.
Our study also shows that immigrants were paid less on average than domestic inventors, despite being more productive in terms of patenting. The precise source of this wage penalty is difficult to pin down; however, inventors from other marginalized groups, such as black and female inventors, were also paid less than similarly productive white males. Our evidence is therefore consistent with classic notions of discrimination, where the wage income of certain types of individuals in the market is lower due to factors unrelated to their productivity.
Overall, our study suggests that immigrant inventors were vital to U.S. competitiveness, despite their lower wages. Although high skill migration is not costless – it is possible that immigrant inventors might displace domestic inventors, for example – an inflow of foreign talent may create positive benefits through improved skills, innovation, and other spillovers. Technological innovation is a central determinant of long-run economic growth, and access to the best inventors matters, regardless of their country of origin.