Healthcare registries, otherwise known in Sweden as national quality registries (NQRs), have progressed from being a patient-focused system supporting medical results to become the basis of a health policy steering instrument called regional comparisons (RCs). This article seeks to explain RCs as an unintended consequence of the NQR development, by utilizing the concepts of policy entrepreneurs and streams of impact: the problem stream (problem perceived), the policy stream (what is valid), and the political stream (governmental objectives). The empirical contribution lies in insights on how the RCs have developed as an unintended consequence of entrepreneurial deliberate action in the process of creating NQRs. These findings are based on documents, interviews, and previous research in the social sciences. The article also argues for a critical understanding of public knowledge management (PKM) related to experiences in the development of NQRs regarding how to use knowledge in healthcare government. This article highlights how knowledge generated in quality systems based on registries could imply a stronger role for authorities in exerting control over the medical profession. It also discusses the potential use of research evidence on NQRs as a base for more efficient policymaking.