Marit Tanke, MD, PhD, a Commonwealth Fund Harkness Fellow, walks us through her research to analyze high-need, high-cost patients across four countries — including her methodology, how costly these patients are, who these patients are, and how they use health care.

Jose Figueroa, MD, a hospitalist at Brigham and Women’s Hospital and a researcher at Harvard School of Public Health and Harvard Medical School, has been researching who patients with complex needs are and helped created a model for identifying population segments within this broad category.