Christian Groth

Too little or too much R&D?

According to the first generation models of endogenous growth based on expanding product variety, the market economy unambiguously generates too little R&D. Later, by disentangling returns to specialization from the market power parameter, it was shown that with sufficiently low returns to specialization too much R&D can occur. The present paper takes a step further, disentangling the market power parameter from the capital share in final output. We show that this helps finding too much R&D as well. In addition, by differentiating between net and gross returns to specialization it is demonstrated what drives the differing inefficiency results in this literature. The decisive factor behind excessive R&D is the implicit presence of negative externalities of increased specialization. Empirically, an advantage of the more general framework is better agreement with the observed level of markups and the observed falling tendency of the patent/R&D ratio.

A New-Growth Perspective on Non-Renewable Resources

This article reviews issues related to the incorporation of non-renewable resources in the theory of economic growth and development. As an offshoot of the new growth theory of the last two decades a series of contributions have studied endogenous technical change in relation to resource scarcity. We discuss the main approaches within this literature and consider questions like: How is the new literature related to the wave of resource economics of the 1970s? What light is thrown on the limits-to-growth issue? Does the existence of non-renewable resources have implications for the controversies within new growth theory?

Some unfamiliar dynamics of a familiar macro model a note

The idea that for small disturbances the full employment equilibrium is stable while for large disturbances it is unstable was coined by Leijonhufvud in the notion of a “corridor”. We discuss the existence of a corridor in the standard Keynesian-monetarist textbook macro-model. It turns out that though the full employment steady state of this model may be locally stable — which is the case when the well-known Cagan condition holds — the model is never globally stable. This is due to the inherent non-linearity in the demand for money function, arising from non-negativity of the nominal rate of interest. Thus, perhaps surprisingly, the Cagan condition is both necessary and sufficient for the existence of a corridor in the Keynesian-monetarist model.

Medium-Term Fluctuations and the 'Great Ratios' of Economic Growth

Evidence for the OECD countries show that the “great ratios�?, such as the unemployment rate, factor shares, Tobin’s q and the investment-capital ratio, fluctuate significantly on medium-term frequencies of 10-40 years duration. To explain these medium-term fluctuations, we establish a macro-dynamic model where the q-theory of investment is combined with sluggish real-wage adjustment in the labour market. In this framework, responses to shocks show persistence and amplification. A high degree of real-wage rigidity combined with a low elasticity of factor substitution leads to damped internal oscillations and hump-shaped impulse-response functions.

Do Mincerian Wage Equations Inform How Schooling Influences Productivity

We study the links between the Mincerian wage equation (the cross-sectional relationship between wages and years of schooling) and the human capital production function (the causal effect of schooling on labor productivity). Based on a stylized Mincerian general equilibrium model with imperfect substitutability across skill types and ex ante identical workers, we demonstrate that the mechanism of compensating wage differentials renders the Mincerian wage equation uninformative for the human capital production function. Proper identification of the human capital production function should take into account the equilibrium allocation of individuals across skill types.