constraints of the statistical agencies, the demographics database should be built, to the maximum extent possible, using existing data.

Full development of nonmarket accounts also requires further research and data development directed toward defining and measuring output. It is not always obvious what the outputs associated with various nonmarket activities are, especially in such service-oriented areas as education, health, social services, culture and the arts, and recreation. Frequently, in difficult-to-measure sectors, the value of output is not measured directly, but set equal to the aggregate value of the inputs used in its production. Accordingly, little is known about growth, quality improvements, or productivity in these sectors. The data that will be needed to create independent output measures are discussed throughout the report. We offer numerous recommendations on this topic and more generally about the next steps needed in research and data development to advance nonmarket accounting.