Ability, Moral Hazard, Firm Size, and Diversification
分析经理与所有者之间的代理问题如何影响企业的最优规模和多元化程度，发现经理能力越高，企业规模越大、多元化程度越高，且多元化是对代理问题的优化反应。
agency problem between the firm's managers and owners. The agency relationship, together with a span-of-control managerial technology, determines an optimalfirm size and degree of diversification that are increasing in the manager's ability and therefore positively correlated cross sectionally. I compare the benefits of merger with those achieved by using compensation contracts based on relative performance and show that, for a particular parameterization, the relative value of merger is a nonmonotonic function of the correlation between the productivity signals of the two firms. * Neoclassical microeconomic theory has generally treated the firm as being identical to a technologically determined production function. Nevertheless, it is widely recognized that this cost-curve approach is more appropriately applied to plants within a firm than to the determination of firm size or structure itself. One aspect of firm structure that has received especially little attention in the economic literature is diversification.' In particular, the literature has not succeeded in distinguishing the benefits of efficiently using capital in production from the benefits to common ownership of the capital. If joint use of capital creates efficiencies in the production of two or more goods, the joint use could in principle be achieved by contracting over the use of the separately owned factors. This ownership structure does not preclude the efficient use of factors. Further, even if technological scope economies create incentives to diversify, they cannot explain all diversification, because much that we observe is between products that are (apparently) unrelated in production technology or demand. The purpose of this article is to analyze the incentives of firms to diversify in an economy comprising managers and capital owners whose interests do not necessarily coincide and in which information is generally not perfect. I derive the implications of the principalagent relationship between owners and managers of firms for the optimal structure of the firm in a competitive environment. Diversification is shown to be an optimal response to