In a landmark article published 50 years ago, Avedis Donabedian proposed using the triad of structure, process, and outcome to evaluate the quality of health care. That triad, along with his eventual seven pillars of quality, continues to inform efforts to improve care.  
New England Journal of Medicine
2016
Ayanian JZ, and Markel H
http://www.nejm.org/doi/pdf/10.1056/NEJMp1605101