Sobre la teoría del crecimiento económico

Resumen

Investment has two different effects: the stock of capital is increased and thereby additional productive capacity is created (capacity effect) and at the same time income is created (multiplier effect). Because net investment in a single period is small in relation to the total stock of capital the capacity effect may be neglected in the short run. The Keynesian System does not take into consideration the capacity effect at all and, therefore, is a tool for short-period analysis only. DOMAR and HARROD independently developed models considering both the capacity and the income effect of investment. These models allow to derive an equilibrium path of growth. The equilibrium rate of growth is equal to the relation between the rate saving and the capital coefficient. The remarkable similarity between growth models and the well-known Samuelson-model showing the interaction between the multiplier and the principle of acceleration is only a formal one. SAMUELSON formulates the principles of acceleration as an investment function. On the other hand growth models contain no investment function at all. They only demonstrate how capital stock and real income have to grow if there is to be no excessive capacity on the one side and no capital shortage on the other. This path of growth is a so-called dynamic or "moving equilibrium". Growth models do not bring out the answer to the question of which forces keep the process of capital accumulation going. In this respect dynamic equilibrium analysis is different from a sequence analysis. A moving equilibrium can only be attained if capital stock, income, and other variables are growing with a certain regularity. Regular, steady movements, however, can only be found in the trend of the development and, therefore, growth models are pure trend models. But at the same time the dynamic equilibrium is also a useful tool of trade cycle theory. The trade cycles are explained as short-run deviations from the equilibrium path of development. To-day growth models are still incomplete systems because they do not consider the influence of the development of labour force. One way to complete these models in this respect would be the inclusion of a function like that developed by COBB and DOUGLAS. Another important improvement would be the subdivision of the economy into sectors.