The conceptual framework behind the model of aggregate U.S. Employment Service (ES) productivity is described in this report (and the companion volume of appendixes) along with the illustrative estimates of ES productivity using the model. Chapter 1 introduces the question of productivity measurement in a social purpose. Chapter 2 contains a discussion of pertinent research findings and other documents reviewed in order to develop a fundamental understanding of the economic role of the ES. Chapters 3 and 4 identify and analyze the economic and social outputs of ES labor exchange activities. Chapter 5 evaluates the work test aspects of ES enforcement activities. Both chapters 4 and 5 include estimates of the value of ES outputs on the basis of fiscal year 1974 data. Chapter 6 combines illustrative value estimates of output and transfer savings by State and also reports on a sensitivity analysis of these estimates to uncertainty affecting various dimensions of the management process. Conclusions and recommendations are summarized in chapter 7. (WL)