This paper presents a paradigm for evaluating an inter-organizational relationship (IOR) wherein two or more independent organizations agree to pool their authority, resources, and energies in order to achieve the goals they desire. Indicators of IOR effectiveness are clustered into four major categories: organizational situations, structural characteristics, relational characteristics, and process characteristics. Organizational characteristics conducive to a collaborative IOR include the existence of potential resources, a generally cooperative environment, and congruence between the organization's goals and IOR goals. Structural characteristics of IORs include coordinating mechanisms, demographic conditions, and resource contributions. Relational characteristics of IORs include interactions among individual representatives of member organizations, and complex and multiple ties at various levels. Process characteristics of IORs include degree of formality, features of the exchange process, and patterns of influence. Evaluations of IORs need to attend to these four components in the paradigm. (BW)