INVESTMENT AND TECHNICAL PROGRESS
该模型认为增长与投资相关，通过“边看边学”的外部性实现，政府可通过税收政策影响增长路径，即使结构相同的经济体也可能因随机税收政策而呈现不同的增长轨迹。
Models in which the growth rate is exogenous provide no role for government in determining growth. In our model, growth is associated with investment, through externalities from "learning by watching, " rather than with the level of the capital stock. Presumption of a technical progress function with first increasing and then decreasing returns leads to multiple steady-state growth equilibria. There is also an explicit role of government policy in setting tax rates on output. It follows that two economies with identical structures and stochastic tax policies may exhibit very different growth paths over sustained periods, although the stationary distribution of growth rates is the same. Given the desirability in principle of subsidizing investment, various practical methods are considered. Copyright 1992 by Oxford University Press.