[1] HARVARD UNIV, SCH MED, DEPT SOCIAL MED & HLTH POLICY, BOSTON, MA 02115 USA
[2] HARVARD UNIV, SCH PUBL HLTH, DEPT HLTH POLICY & MANAGEMENT, BOSTON, MA 02115 USA
[3] HARVARD UNIV, SCH MED, DEPT HLTH CARE POLICY, BOSTON, MA 02115 USA
[4] HARVARD UNIV, BRIGHAM & WOMENS HOSP,SCH MED,DEPT MED, DIV GEN MED,HLTH SERV & POLICY RES SECT, BOSTON, MA 02115 USA
[5] HARVARD UNIV, SCH MED, DEPT RADIOL, BOSTON, MA 02115 USA
[6] HARVARD UNIV, SCH MED, DEPT PREVENT MED & CLIN EPIDEMIOL, BOSTON, MA 02115 USA