Aggregate Implications of Innovation Policy

We examine the quantitative impact of policy-induced changes in firms’ innovative investment on growth in aggregate productivity and output in a model that nests several of the canonical models. We isolate two statistics, the impact elasticity of aggregate productivity growth with respect to aggregate innovative investment and the degree of intertemporal knowledge spillovers in research, that shape the model’s predicted dynamic response to a change in the innovation intensity of the economy. Given measures of these statistics, there is only modest scope for increasing aggregate productivity and output over a 20-year horizon with uniform innovation subsidies to firms’ investments in innovation of a reasonable magnitude, but the welfare gains may be substantial.