The purpose of this paper is to present a case study of the application of survey data to government policy analysis. For over two years, Canadians have been engaged in a major review of their social security system. One aspect of this review has been the development of realistic proposals for a guaranteed annual income for Canadians. As part of the review process, the Federal Government has tried to develop and apply the analytical capabilities necessary to evaluate the policy implications of alternatives as they arose. One such development was the construction of a micro-simulation model based on a comprehensive income survey of the Canadian population. The purpose of this model was to estimate the costs and effectiveness of the given proposals.