During the early stages of the policy analysis profession, faith in the methodologies of the analyst rested on a rarely articulated assumption that information was available and appropriate. Attitudes about information have become much more complex in the decades that have elapsed since the practice of policy analysis began. Advances in information technology have produced what is often called “big data” and contributed to efforts that mine the information found in social media. Harold Wilensky suggested that the information relevant to policy includes questions, insights, hypotheses and evidence. The choice of tools or analytic method can predetermine the information source. The practice in the twenty-first century of involving both private sector and public sector institutions in policymaking has led to difficulties when the private sector considers information to be of a proprietary nature. The faith in information was particularly important in the emergent evaluation field.