Purpose: In recent years, the clinical performance of named cardiac surgeons in England has been disclosed. This paper aims to explore the nature and impact of disclosure of clinical performance., Design/methodology/approach: The paper draws on literature from across the social sciences to assess the impact of disclosure, as a form of transparency, in improving clinical performance. Specifically, it employs the "programme theory" of disclosure., Findings: The "programme theory" of disclosure involves identification, naming, public sanction and recipient response. Named individual (consultant) surgeons have been identified through disclosure but this masks the contribution of the clinical team, including junior surgeons. Mortality is the prime performance measure but given low mortality rates, there are problems interpreting this measure. The naming of surgeons has been achieved through disclosure on web sites, developed between the health-care regulator and the surgical profession itself. However, participation remains voluntary. The intention of disclosure is that interested parties (especially patients) will shun poorly performing surgeons. However, these parties' willingness and ability to exercise this sanction appears limited. Surgeons' responses are emergent but about a quarter of surgeons are not participating currently. Fears that surgeons would avoid high-risk patients seem to have been unrealised. While disclosure may have a small effect on individual reputations, the surgical profession as a whole has embraced disclosure., Originality/value: While the aim of disclosure has been to create a transparent medical system and to improve clinical performance, disclosure may have the opposite effect, concealing some performance issues and possibly strengthening professional autonomy. Disclosure therefore represents greater transparency in health-care but it is uncertain whether it will improve performance in the ways that the policy intends.