150 Years of American Invention: Methodology and a First Geographical Application

This paper makes use of American patent data to shed light on the geographical history of invention, and introduces a methodology (the Wellesley Technology Concordance) which creates matrices describing the distribution of patents by 43 industries of manufacture and 50 sectors of use, along with all intersectoral interactions. National data (1840-1996) are presented and summarized, along with state-level totals (1883-1996). A simple constant market share analysis demonstrates the usefulness of the WTC methodology in the exploration of regional differences over time, illuminating the links between the continued success of key sectors and the emergence or submergence of geographic regions as leading inventors.