Concerns about the nation's health and health systems have returned to the forefront of public debate in the United States. Rising health care costs and persistent gaps in the quality, safety, and accessibility of health services raise troubling questions about the future. 1–3 Despite spending more on health services than any other nation, Americans continue to experience higher rates of premature death and preventable diseases and disabilities, and lower life expectancies than their counterparts in many other industrialized countries. 4,5 At the same time, the threat of terrorism and emerging infectious diseases, such as SARS, have brought increasing public attention to gaps and inadequacies in the basic infrastructure that protects health at the population level. Moreover, the rapidly growing obesity epidemic has highlighted the difficulties faced by the health system in addressing the myriad social, behavioral, physical, and environmental conditions that precipitate disease and injury.

Addressing these problems will require targeted efforts to strengthen the nation's public health infrastructure and to ensure that governmental public health agencies can engage effectively with other components of the health system to mount effective, population-based prevention and health protection activities. 6 Historically, such efforts have been hindered by an under-resourced and deteriorating public health infrastructure 7,8; by institutional, professional, and cultural differences between medical and public health settings 9,10; and by gaps in the evidence base concerning what constitutes effective public health practice. 6,11 Over the past two years, the federal government has allocated more than $2 billion in new funding to improve public health system preparedness for bioterrorism and other emerging health threats. Along with these new resources, the public health community urgently needs a strong evidence base on how best to allocate and apply these funds. The nation's experience with health care financing clearly indicates that increased spending alone will not guarantee improved health.