This is an effort to state a professional consensus on how market and opinion research for public use should be assessed and what determines how useful, sound, and credible particular research may be in such applications. The guidelines which follow outline the criteria which are important in the evaluation of the validity and reliability of research results and of the weight to be given to them. It was written because research is being used increasingly for public purposes: 1. As evidence in legal cases; 2. As evidence in testimony at government and other public hearings; 3. In support of advertising or publicity claims for products, candidates, or causes; 4. As support for news stories and features which appear in the press and other media.