The objective of the Public Health Classifications Project is to 'develop and endorse a higher-level classification that captures the breadth and scope of public health activity and provides a unified framework for multiple uses'. Such a unified framework will assist in improving the quality and consistency of reported information on public health activity, performance, investment and expenditure. The National Public Health Partnership funded the project in response to recommendations from the 2002 Public Health Performance Project. 1 During the early scoping stages of the Public Health Classifications Project, it became apparent that a simple, one-dimensional classification system for public health could not satisfy the needs, or reflect the diverse world-views, of its disparate potential users. To provide a single 'unified framework' for multiple public health uses, a multi-dimensional classification was needed.