Before revision: Where do firms innovate? Mapping their locations in technological space is difficult, because it is high dimensional and unstructured. We address this issue by using a method in computational topology called the Mapper algorithm, which combines local clustering with global reconstruction. We apply this method to a panel of 333 major firms' patent portfolios in 1976--2005 across 430 technological areas.
After revision: We propose a new method to characterize firms' inventive activities via topological data analysis (TDA) that represents high-dimensional data in a shape graph. Applying this method to a panel of 333 major firms' patent portfolios in 1976--2005 across 430 technological areas.