As a final chapter in the research to evaluate the impact of the Michigan township extension experiment, this report focuses on why and how change came about, what factors appear to be most closely related to change, and the ways in which change agents can most effectively help bring about change. In the experiment, extension agents worked intensively with farm families in five township areas for five years; one of the major objectives was to develop and test techniques for increasing agricultural output. It was found that farmers in experimental areas adopted improved farm practices faster and stepped up their use of inputs more than farmers in matched control groups. Average value of total farm output increased $5,600 on experimental farms as compared to $3,400 on control farms. Net farm earnings for the experimental sample increased an average of $1,646 as compared with $938 for the control sample. Benefit-cost analysis showed that the program cost $117 per farm per year. The differential increase in net earnings during the five-year experimental period exceeded the total costs of the program by two and one-half times. (Included are 32 tables, 14 references, and a model of relationship among types of variables studied.) (eb)