Allocation of public health resources should be based, where feasible, on objective assessments of health status, burden of disease, injury, and disability, their preventability, and related costs. In this article, we first analyze traditional measures of the public's health that address the burden of disease and disability and associated costs. Second, we discuss activities that are essential to protecting the public's health but whose impact is difficult to measure. Third, we propose general characteristics of useful measures of the public's health. We contend that expanding the repertoire of measures of the public's health is a critical step in targeting attention and resources to improve health, stemming mounting health care costs, and slowing declining quality of life that threatens the nation's future.