Offering a contribution to additional clarity in the debate about the viability of "rural development" as an explanatory concept and program of action, the paper presents details of a causal model which underlies the approach to rural development taken by a W. K. Kellogg Foundation supported program in eastern Washington called "The Partnership for Rural Improvement (PRI)." Assumptions indicate the scope of concern as a prelude to discussion of the useful attributes of a well-conceived rural development model. Graphic and narrative forms (including process, structural, and functional requirements) describe specific characteristics of the PRI model. Data collected over the five-year period since the model was initiated in 1976 illustrate and preliminarily test specific "middle range" theoretical generalizations. Surveys, case studies, client assessments, detailed interviews with selected program participants, and content analysis of program documents provide evidence concerning the generalizations. Evidence suggests that the model operates effectively and that it has potential for successful transfer to regions beyond where it has initially been operationalized. Nonetheless, further research would undoubtedly be helpful in expanding the conceptual and operational utility of the model. (Author/NEC)