Estimation of demand systems using both time series and cross section data

Summary This article deals with three models of complete systems of demand equations (Rotterdam model, AIDS and CBS model). After the models and the theoretical restrictions have been described the parameters are estimated subject to an increasing number of restrictions and using aggregate time series for the Netherlands on five commodity groups. As the initial results are not altogether satisfactory an attempt is made to improve the estimates by combining the time-series information with cross section data from the Dutch 1974/1975 budget survey. While the revised estimates of the income elasticities are more plausible than the initial ones, the reverse is true for the estimated price elasticities. This paper originated when I was a student of economics at the University of Amsterdam. I am greatly indebted to J.G. Odink who never failed to support and inspire me while I worked on this paper. Also I thank J.S. Cramer, D.A. Kodde and J. van Driel for their comments on an earlier draft, and G. Ridder for his econometric advice. Finally the comments of two anonymous referees are gratefully acknowledged. Of course all remaining errors and omissions are my own.     

Optimal economic growth and non-stable population

Summary This paper analyses optimal economic growth when the (exogenous) rate of population growth changes. The optimal growth path is characterized by a strikingly straightforward generalization of the traditional steady-state Golden Rule of Accumulation. The comparative statics results allow for a generalization of Samuelson's (1975) analysis of the lower-bound for the optimal rate of population growth. It is shown that under plausible assumptions the optimal savings rate follows an inverted U-shaped or U-shaped pattern during periods of demographic transition, according to whether the growth rate of births is falling or rising.