中文摘要：

合作社效率内涵应包含两个方面：一方面可理解为合作社的投入产出效率,属于其内部效率;另一方面指合作社对社会总福利的贡献度,可视为其外部效率。合作社对投入产出效率的追求具有现实合理性。相同的目标函数是衡量合作社效率的前提条件。规模影响合作社效率,理论上存在最优规模;内部治理因素对合作社效率的影响是至关重要的,其中社员结构及素质、经理（管理者）的人力资本是关键;制度环境、资源环境和市场环境等外部环境通过作用于合作社的内部治理要素,影响合作社的资源配置与利用,进而影响合作社效率。从政策层面来看,向社员（包括经理）投资是提高合作社效率的关键。此外,有必要考虑外部环境的作用。

英文摘要：

Efficiency is an everlasting issue which is of special importance to any economic society.In the modern market economy society,inefficiency means losing competitiveness.It is imperative for cooperatives to improve economic efficiency,thus maintaining their competitiveness.Generally there are two aspects in the concept of cooperative efficiency.On the one hand,it can be understood as cooperative input-output efficiency,which means to obtain maximum output at a certain level of input,or to realize minimum input at a certain level of output.This belongs to internal efficiency for cooperatives.On the other hand,it also can be regarded as external efficiency for cooperatives,which means the comprehensive efficiency of cooperatives in promoting reasonable allocation of social resources among various departments while pursuing internal efficiency.In short,external efficiency refers to cooperatives＇ contribution to total welfare in society.However,the external efficiency for cooperatives,in other words,the ideal Pareto optimality,does not exist in reality and it would be difficult to carry on quantitative evaluation.Therefore,it is realistically reasonable for cooperatives to pursue input-output efficiency. The cooperative efficiency is determined by the chosen objective function.Cooperatives with different functions have different objective functions.For example,objective functions for marketing cooperatives and for purchasing cooperatives are different.Identical objective function is the basic premise for measuring cooperative efficiency.It is an accidental phenomenon for cooperatives to realize efficiency because of information asymmetry,poor management etc.Generally inefficiency manifests in cooperatives.Therefore,there is practical significance of adopting effective methods to measure cooperative efficiency accurately and in discussing profound reasons affecting the efficiency. The influence of scale on cooperative efficiency is obvious.It is generally believed that there exists an optimal scale for each cooperati