whether that will continue to be so if learning is explicitly incorporated and portfolio and other benefits fully valued, remains to be seen. Certainly, difficult though it undoubtedly is, we judge that further cost benefit analysis (CBA) of DG is likely to prove productive, with some of the uncertainties diminishing with time. CBA continues to provide, in our view, the most comprehensive and systematic framework for evaluating individual projects, or groups of projects, from the perspective of society as a whole. However, the approach can, and should, be extended to accommodate general equilibrium impacts/macroeconomic effects.