中文摘要：

农户与合作社之间的关系（即“农社关系”）对农户农业收入增长的影响是合作社政策效果评价中的重要问题。本文首先构建了一个农户专用性投资影响农社关系，进而导致农户农业收入差异的理论框架；然后利用中国15省微观调查数据建立内生转换回归（ESR）模型，通过构建反事实场景分析了差异化农社关系下农户的农业收入差异。研究结果表明：农户专用性投资有助于形成紧密的农社关系；随着农社关系由非社员逐步向影子社员、松散社员和紧密社员转变，农户的农业收入分别提高8．01％、1．65％和2．46％；而对政府更为关注的低收入农户而言，当农社关系由松散社员转向紧密社员时，合作社的扶贫增收效应曼明显．

英文摘要：

The relationship between farmers and cooperatives can have an impact on farmers＇ agricultural income growth. This can be used to assess cooperatives＇ policy performance. This article constructs a theoretical framework including three components, namely, farmers＇ specific investment, relationship between farmers and cooperatives, and farmers＇ agricultural income. Furthermore, it builds an endogenous switching regression （ESR） model by using the survey data from 15 provinces in China. By constructing a counterfactual, the study analyzes the difference in farmers＇ agricultural income caused by differentiated relationship between farmers and cooperatives. The results show that farmers＇ specific investment conlributes to the formation of a closer relationship between farmers and cooperatives. Farmers＇ agricultural income is shown to have a gradual increase by 8.01%, 1.65% and 2.46% with the change of relationship between farmers and organizations from no formal relationship to a nominal one, an incompact one and a tight one. For low-income farmers, their income growth appears more obvious when the relationship between farmers and cooperatives has changed from an incompact one to a tight one.