Stakeholders in many cities and counties have expressed interest in conducting their own cost analysis such as the one done for the New York/New York Initiative which provided powerful evidence of supportive housing’s ability to produce outcomes that policy makers want-reductions in inappropriate use of emergency public services, and their associated costs. This guide lays out the issues that any jurisdiction needs to think about before committing itself to that endeavor. Its intended readers include city and county agencies; individual homeless assistance providers; homeless advocacy groups; associations and coalitions of providers, advocates, and consumers; foundations and private homeless assistance funders; and planning agencies, commissions, task forces, and committees.