In the USA, where public reporting of data on clinical performance is most advanced, comparative performance information, in the form of 'report cards', 'provider profiles' and 'physician profiling', has been published for over a decade. Many other countries are now following a similar route and are seeking to develop comparative data on health care performance. Notwithstanding the idiosyncratic nature of US health care, and the implications this has for the generalizability of findings from the USA to other countries, it is pertinent to ask what other countries can learn from the US experience. Based on a series of structured interviews with leading experts on the US health system, this article draws out the key lessons for other countries as they develop similar policies in this area. This paper highlights three concerns that have dominated the development of adequate measures in the USA, and that require consideration when developing similar schemes elsewhere. Firstly, the need to develop indicators with sound metric properties - high in validity and meaningfulness, and appropriately risk-adjusted. Secondly, the need to involve all stakeholders in the design of indicators, and a requirement that those measures be adapted to different audiences. Thirdly, a need to understand the needs of end users and to engage with them in partnerships to increase the attention paid to measurement. This study concludes that the greatest challenge is posed by the desire to make comparative performance data more influential in leveraging performance improvement. Simply collecting, processing, analysing and disseminating comparative data is an enormous logistical and resource-intensive task, yet it is insufficient. Any national strategy emphasizing comparative data must grapple with how to engage the serious attention of those individuals and organizations to whom change is to be delivered.