The economic distinction between technological and market information offers a useful guide to the relationship between information and policy. The two types create different problems for markets and require different emphases in public policy, focusing on either the production or the distribution of information. The interaction of the two types creates familiar policy problems such as underinvestment in information, adverse selection and moral hazard. Indicators and other means of dealing with such problems constitute policies and demonstrate not only the importance of information for policy but the necessity of policy for information.