Lean six sigma improves performance not outcomes: Past limitations, potential solutions

Research supports the transformational impact of Lean Six Sigma on the US healthcare system over the past two and a half decades, now commonly referred to as Lean Healthcare (LH).¹ These tools have facilitated reduction in medical errors, wait times, and cost of care delivery, while increasing specific quality metrics such as patient turnover and patient satisfaction that are centered on patient safety and the reduction of medical errors.^2-5 Six Sigma, a term derived from manufacturing quality control indicating a process operating within ±6σ limits (∼3.4 defects per million opportunities), also has increased operational profitability, though without reducing costs for consumers or insurers.⁶ While outcomes serve as an approximate endpoint for improved health states, national spending continues to outpace other high-income countries without corresponding outcome gains. This review highlights lessons from wide-scale implementation of Lean Six Sigma (LSS): its impact on costs, quality metrics, and health outcomes-with attention to potential in small practices.