Public health is concerned with improving health within groups of people, from small communities to large nations. It focuses on preventing disease, disability and premature death, and promoting optimal health through education and emphasis on healthy behaviors and a healthy environment. Public health promotes a stronger, more engaged population with a greater understanding and awareness of how lifestyle choices and social and economic conditions can positively or negatively impact health outcomes and quality of life. Presenting health data for a population or community helps us to understand the health issues in that community and the interaction between health and the conditions in which people live. This in turn can help inform public policy development that can protect and promote health.