"Population Health" provides guidance for ACOs and others taking health risk
"Population Health -Creating a Culture of Wellness" (http://www.amazon.com/Population-Health-Creating-Culture-Wellness/dp/076378043X/ref=sr_1_1?ie=UTF8&qid=1298394113&sr=8-1) is a new book that provides a comprehensive overview of the issues involved in understanding and managing the health of large groups of people. Coauthored by David Nash, Dean of Thomas Jefferson University's School of Population Health, the book is separated into section