Six Sigma
Six Sigma is another model for improvement. The term comes from the use in statistics of the Greek Letter (sigma) to denote Standard Deviation from the mean. 6 sigma is equivalent to 3.4 defects or errors per million.
Six Sigma is a measurementbased strategy for process improvement and problem reduction completed through the application of improvement projects. This is accomplished through the use of two Six Sigma models: DMAIC and DMADV.
 DMAIC (define, measure, analyze, improve, control) is an improvement system for existing processes falling below specification and looking for incremental improvement.
 DMADV (define, measure, analyze, design, verify) is an improvement system used to develop new processor products at Six Sigma quality levels.
Applying Six Sigma to Patient Care:
https://www.isixsigma.com/industries/healthcare/applyingsixsigmapatientcare/
