The National Health Security Strategy calls for a systematic quality improvement efforts to improving health security. In addition, since 2001, billions of dollars have been spent on public health emergency preparedness at the federal, state, and local levels. Policy makers must now ask has this investment been effective, and in what way to measure this investment. Whether the goal is to ensure accountability to policy makers or to facilitate quality improvement, valid and reliable measures of preparedness are needed. Measuring and assessing the state of the nation's preparedness, however, are challenging. This article explores the current measurement climate and potential for improvement.