Assessing the Evidence of Six Sigma and Lean in the Health Care Industry

In Brief Background Popular quality improvement tools such as Six Sigma and Lean Systems (SS/L) claim to provide health care managers the opportunity to improve health care quality on the basis of sound methodology and data. However, it is unclear whether these 2 quality improvement tools actually improve health care quality. Methods The authors conducted a comprehensive literature review to assess the empirical evidence relating SS/L to improved clinical outcomes, processes of care, and financial performance of health care organizations. Results The authors identified 177 articles on SS/L published in the last 10 years. However, only 34 of them reported any outcomes of the SS/L projects studied, and less than one-third of these articles included statistical analyses to test for significant changes in outcomes. Conclusions This review demonstrates that there are significant gaps in the SS/L health care quality improvement literature and very weak evidence that SS/L improve health care quality. Division of Management, Policy, and Community Health and Fleming Center for Healthcare Management, University of Texas School of Public Health, Houston (Drs DelliFraine and Langabeer II), and Yale University School of Medicine and Management, New Haven, Connecticut (Dr Nembhard).