Risk communications should focus on critical information that is either missing or available but misunderstood. Identifying the facts that might be worth communicating requires normative analysis of the decisions that people face, followed by descriptive study of what they currently believe. This article discusses approaches to accomplishing these tasks. Each requires the skills of both social and natural scientists. So does ensuring that risk analysis plays an appropriate role in societal decision-making and is afforded the credibility that it deserves.