Joint research with
Scott Stern (MIT) is exploring the determinants of innovative capacity across countries using time series/cross-section data ("Measuring the "Ideas" Production Function: Evidence from International Patent Output," draft working paper, July 1998). Using international patenting as a weighting variable, Porter and Stern have devised an index of national innovation capacity. The data has also been employed to directly estimate critical parameters of the ideas production function, a central element in economic growth theory.