title: Assessing the evidence of Six Sigma and Lean in the health care industry.
abstract: 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.
authors.affiliation: Division of Management, Policy, and Community Health and Fleming Center for Healthcare Management, University of Texas School of Public Health, Houston, TX 77030, USA.
authors.forename: Jami L
authors.initials: JL
authors.lastname: DelliFraine
authors.forename: James R
authors.initials: JR
authors.lastname: Langabeer
authors.forename: Ingrid M
authors.initials: IM
authors.lastname: Nembhard
mesh_terms: D003362:Cost-Benefit Analysis; D017598:Efficiency, Organizational; D055317:Evidence-Based Practice; D019981:Health Care Sector; D006801:Humans; D010043:Outcome and Process Assessment, Health Care / Q000379:methods*; D011787:Quality of Health Care; D017749:Total Quality Management / Q000379:methods*