A history of collaboration in US invention: changing patterns of co-invention, complexity and geography.

Research suggests that increasing collaboration in knowledge production is explained by rising complexity of knowledge. Yet, there is little long-run, systematic, empirical evidence on the relationship between complexity and collaboration. A new database is introduced that identifies all (co-)inventors on more than 3 million US patents between 1836 and 1975. Empirical analysis reveals (i) collaboration on US patents began to increase in the 1940s; (ii) there is a robust positive relationship between complexity and collaboration; and (iii) increasing complexity is associated with local rather than nonlocal collaboration. [ABSTRACT FROM AUTHOR]