tailieunhanh - foundations of international macroeconomics phần 7

khóa học cũng như các khóa học sau đại học về kinh tế vĩ mô và tài chính quốc tế. Mỗi chương kết hợp một mảng rộng lớn và bằng chứng thực nghiệm chiết trung của. Đối với các sinh viên bắt đầu, những ví dụ cung cấp động cơ thúc đẩy và hỗ trợ trong việc tìm hiểu giá trị thực tế của các mô hình kinh tế | 474 Global Linkages and Economic Growth 1988 Aghion and Howitt 1992 and G. Grossman and Helpman 1991 . In this section we will look at a couple of core models underlying this research and we will also examine the empirical case for new growth theory. It is helpful to think of new growth theory as consisting of two pieces. One is a macro piece that shows how an economy can sustain indefinite growth in per capita income even in the absence of exogenous technological change. The other is a micro piece that attempts to endogenize changes in technology by introducing an explicit research and development sector. We begin with the macro side. The Ail Model In the Solow model there are diminishing returns to scale in capital holding efficiency labor constant. It is precisely for this reason that the economy eventually settles down to a steady-state growth path in which the capital-labor ratio is constant and where the only source of growth in output per capita is exogenous technological progress. The AK model takes its name from the assumption that at the aggregate level output is linear in capital so that there are constant rather than diminishing returns to raising the capital-labor ratio. While fundamentally mechanical it is really a model of perpetual growth through capital deepening rather than innovation the AK model nonetheless provides a good introduction to the macro mechanics of new growth models. Consider a closed economy in which the standard engines of neoclassical growth are absent there is no technological progress and the population s size is constant. The infinitely-lived representative consumer-manager has time-additive isoelastic preferences given by S 1 - 5 7 ơ As usual equilibrium per capita consumption obeys 1 I I _ 1 G l ơ AO 1 G 1 I I 62 p ct J which is the familiar first-order Euler condition for the isoelastic case rearranged in a way that will prove convenient. Each worker manages his own firm the production technology of which is yt - Akt