Disease prevention has always been the preferred option for promoting health and reducing disease rates. For many, this health argument is reason enough to invest in prevention, economics aside. Others, citing scarce resources, advocate a careful assessment of the costs and savings associated with prevention. It initially costs more to deliver preventive services; the savings the resulting health benefits will incur over time are less clear. Some reports claim that effective prevention programs would save the nation billions of dollars,1 while others predict the reverse.2 Economists and columnists have argued that prevention rarely saves money and is inherently no more cost-effective than disease care.3-5 For policy makers—caught between an economic crisis, pressure to defer new spending and seize control over escalating health care costs, and a promise to voters to make prevention part of health care reform—resolving whether prevention will help reduce spending is highly relevant.