The United States has supported research and development activity on both the applied and basic research levels for most of its history. The importance of public sector research has often been discussed but its effectiveness has not been adequately reviewed. The need for evaluation of public sector research and development activity is critical in today's political environment to assist policymakers with resource allocation. Methodology for evaluating public sector research and development activity is described and illustrated by the author using in-depth case studies drawn from the research programs at the National Institute of Standards and Technology. These cases range from newly formed federal laboratory research initiatives to well-established research programs. Managerial and evaluative guidelines are enunciated. This work should be of interest to scholars who deal with economics in general, public policy, science policy, and public administration. In addition, practitioners in public administration and managers of public sector research laboratories on federal and state levels should find the information useful. Those who depend on research and development done with public sector money or who use it to supplement their research programs will also be interested.