[Essential functions of public health: emerging topic in health care reform].

In the Americas, health sector reforms are facing the challenge of strengthening the steering and leadership role of health authorities. An important part of that role consists of fulfilling the essential public health functions (EPHFs) that are incumbent on all levels of government. For that, it's crucial to improve public health practice, as well as the instruments used to assess the current state of public health practice and the areas where it needs to be strengthened. For that purpose, the Pan American Health Organization has started an initiative called "Public Health in the Americas," with the objective of defining and measuring EPHFs, as a way of improving public health practice and strengthening the leadership provided by health authorities at all levels of government. This article summarizes conceptual and methodological aspects of defining and measuring EPHFs. The article also analyzes the implications that measuring performance on these public health roles, responsibilities, and activities would have for improving public health practice in the Americas.