Kirsten Ralf

Patents as collateral

This paper studies how the assignment of patents as collateral determines the savings of firms and magnifies the effect of innovative rents on investment in research and development (R&D). We analyse the behaviour of innovative firms that face random and lumpy investment opportunities in R&D. High growth rates of innovations, possibly higher than the real rate of interest, may be achieved despite financial constraints. There is an optimal level of publicly funded policy by the patent and trademark office that minimizes the legal uncertainty surrounding patents as collateral and maximizes the growth rate of innovations.

Do complementary factors lead to economic fluctuations

Abstract In a two-sector overlapping generations model with fixed coefficients the steady state may be indeterminate, if production in the consumption goods sector is more capital intensive than in the investment goods sector. Fluctuations are the consequence of capital-labour substitutions between the two sectors caused by changes in relative input prices.

Hopf Bifurcation from new-Keynesian Taylor rule to Ramsey Optimal Policy

This paper shows that a shift from Ramsey optimal policy under short term commitment (based on a negative-feedback mechanism) to a Taylor rule (based on positive-feedback mechanism) in the new-Keynesian model is in fact a Hopf bifurcation, with opposite policy advice. The number of stable eigenvalues corresponds to the number of predetermined variables including the interest rate and its lag as policy instruments for Ramsey optimal policy. With a new-Keynesian Taylor rule, however, these policy instruments are arbitrarily assumed to be forward-looking variables when policy targets (inflation and output gap) are forward-looking variables. For new-Keynesian Taylor rule, this Hopf bifurcation implies a lack of robustness and multiple equilibria if public debt is not set to zero for all observation.

Publish and Perish: Creative Destruction and Macroeconomic Theory

A number of macroeconomic theories, very popular in the 1980s, seem to have completely disappeared and been replaced by the dynamic stochastic general equilibrium (DSGE) approach. We will argue that this replacement is due to a tacit agreement on a number of assumptions, previously seen as mutually exclusive, and not due to a settlement by ‘nature’. As opposed to econometrics and microeconomics and despite massive progress in the access to data and the use of statistical software, macroeconomic theory appears not to be a cumulative science so far. Observational equivalence of different models and the problem of identification of parameters of the models persist as will be highlighted by examining two examples: one in growth theory and a second in testing inflation persistence.

Countercyclical versus Procyclical Taylor Principles

Assuming inflation is a forward variable in Taylor (1999) model, this paper finds opposite policy rule recommandations with counter-cyclical policy rule parameters (Taylor principle: inflation rule larger than one and bounded upwards) in the case of optimal policy under commitment versus pro-cyclical policy rule parameters (inflation rule parameter below zero) in the case of discretionary policy. For the observed high inertia of the Fed with variations of the nominal policy rate within the range [0%,4%] during the great moderation, the cost of time-inconsistency is negligible for optimal policy. Time-inconsistency cannot be the ultimate argument to reject counter-cyclical Taylor principle.