An Endogenous Growth Puzzle. The knowledge production
function is central to R&D-based growth models. This
paper empirically investigates the knowledge production
function and intertemporal spillover effects using
cointegration techniques. Time-series evidence suggests
there are two long-run cointegrating relationships. The
first captures a long-run knowledge production function;
the second captures a long-run positive relationship
between TFP and the knowledge stock. The results
indicate the presence of strong intertemporal knowledge
spillovers and that the long-run impact of the knowledge
stock on TFP is small. This evidence is interpreted in
light of existing theoretical and empirical evidence on
endogenous growth. pdf. 2005