Although quite important, analysis of these innovation implica-tions has been hampered by the burden of well-known conceptualhypotheses and econometric problems that affect estimation of theproduction function. In addition to these, we retain that a crucialobstacle to the simple use of the production function is repre-sented by the inner heterogeneity that firms have been found toshow in innovation, in particular with respect to their size and spe-cific economic sector. This is a basic pillar of modern economics