Federal agencies in the United States are required to prepare regulatory impact analyses (RIAs) for every major regulatory action they undertake. Increasingly, other OECD countries are imposing similar requirements. However, there has been little examination of the quality of these documents or of the uses to which they have been put in the regulatory process or elsewhere. In this paper we survey previous efforts to evaluate RIAs and find a fair amount of evaluation of RIAs as stand-alone documents, but much less evaluation of their contribution to producing better regulations.