Einzelbesprechungen

Ohne Zusammenfassung     

A system of demand equations for Austria

This paper presents results of parameter estimations of a small system of demand equations for Austria. The functional form of the equations follows the log-linear specification well known as the “Rotterdam”-System. Using annual data from 1954 to 1977 we estimate the absolute price version for a rather aggregated system consisting of four sectors of consumption expenditures. Aitken estimation with and without linear restrictions is the adopted estimation method. Tests for the validity of the general linear restrictions axe performed employing the usual criteria. Relations among the test statistics are discussed. Taking into accountBeaton's [1972] argument of the appropriate use of likelihood ratio tests we present results also after iterating on the restricted error-covariance matrix. The question of negative semidefiniteness of the matrix of price coefficients is examined by inspection of its characteristic roots and the calculation of their approximated asymptotic covariance matrix. Finally, our results are confronted with such of other comparable studies.     

Stabilitätskonzepte am Beispiel Österreichs

Summary This paper examines two aspects of equilibrium — and stability concepts, which go beyond the traditional analyses. Firstly the speed by which a systems returns to the equilibrium position after an initial disturbance and, secondly, the introduction of stochastic elements in the analysis of stability. Both aspects are presented against the background of a simple model of the Austrian economy.It is known that a system of difference equations is stable if the greatest sigenvalue is smaller than one. In trying to estimate confidence intervals it can be shown that an evaluation according to deterministic criteria alone can indeed be misleading, even though the probability of an instable solution is small in the model under examiniation.The speed, by which a system returns to the equilibrium position after an initial disturbance, is measured by the half-life-period. This is the time it takes for the effects of the initial disturbance to be reduced to half their original values. In the model under examination the half-line amounts to one year (real solution) or two years (complex solution) respectively. If we take the stochastic nature of the eigenvalues into consideration, we get, for the 95% level of significance, figures of 3 months to 6 years in the real case. The large spread results from the fact that the half-life-concept is very sensitive even towards minor changes in the eigenvalues.This paper shows that the conventional methods of estimation of coefficients in stability-analyses are not sufficiently accurate.     

Abolition of Raw Milk Quota in the European Union: A CGE Analysis at the Member Country Level

This paper discusses a generic approach to implementing production quotas in an applied general equilibrium framework. The quota rent is interpreted as additional primary factor payments. We analyse the abolition of the raw milk quota and the elimination of export subsidies for dairy products in the European Union at a member country level. The raw milk output increases in Denmark, Ireland, Italy, Luxembourg, the Netherlands and Spain, while it declines in Germany, Greece, Portugal and Sweden. The EU‐wide effect for raw milk production is an output increase of 3% and a price decline of 22%. To assess the robustness of the critical assumption about the raw milk quota rent we apply Arndt and Pearson's Systematic Sensitivity Analysis.     

MDP algorithms for portfolio optimization problems in pure jump markets

We consider the problem of maximizing the expected utility of the terminal wealth of a portfolio in a continuous-time pure jump market with general utility function. This leads to an optimal control problem for piecewise deterministic Markov processes. Using an embedding procedure we solve the problem by looking at a discrete-time contracting Markov decision process. Our aim is to show that this point of view has a number of advantages, in particular as far as computational aspects are concerned. We characterize the value function as the unique fixed point of the dynamic programming operator and prove the existence of optimal portfolios. Moreover, we show that value iteration as well as Howard’s policy improvement algorithm works. Finally, we give error bounds when the utility function is approximated and when we discretize the state space. A numerical example is presented and our approach is compared to the approximating Markov chain method.      

Agriculture's Contribution to Overall Economic Growth: An Application of Kaldor's First Growth Law to Ghana

Abstract: This paper makes use of Kaldor's first growth law to investigate the growth linkages between agriculture and the entire economy, as well as the agricultural and non-agricultural sectors in Ghana. Annual growth rates data used in the analysis to examine the significance of agricultural growth to overall economic growth indicate that growth in the agricultural sector is quite essential for general economic growth. Two-Stage Least Square analysis employed to handle the issue of interdependence between the agricultural and non-agricultural sectors also reveal that the magnitude of the growth linkages between the agricultural and non-agricultural sectors is quite significant. Résumé: le document utilise la première loi de la croissance de Kaldor pour explorer, dans le cas du Ghana, les liens de croissance qui existent entre l'agriculture et l'économic tout entière, et entre le secteur agricole et les autres secteurs. Les données de croissance annuelle utilisées dans l'analyse pour examiner l'importance de la croissance agricole pour la croissance économique globale, font ressortir que la croissancc du sectcur agricole est une condition essentielle de la croissancééconomique générale. La méthode des moindres carrés en deux étapes, à laquelle l'auteur recourt pour traiter la question de l'interdépendance entre le sectcur agricole et les sectcurs non agricoles, révèle également la forte corrélation entre la croissance du secteur agricolc et celle des secteurs non agricoles.