Six Sigma Process Improvement

Six sigma is a process improvement strategy used to optimize all sorts of business objectives such as cost reduction, profitability, production schedules, quality measures, cycle times, inventory levels and so forth. It was first developed by Motorola Corporation in 1981. The process heavily relies on statistical methods applied by teams and individuals who are certified in these special techniques, and who are awarded titles such as "Green Belts," "Black Belts," "Yellow Belts" and so forth depending upon their proficiency with these tools.

The optimization of manufacturing processes, specifically the need to improve quality levels in production processes, was the original impetus for the development of Six Sigma tools and techniques. The field of Operations Research at modern universities (such as Cornell University) teach these optimization tools: ANOVA analysis of variance, process control charts, factor design of experiments, FMEA, Kano analysis, Pareto and Bayesian testing, Poka Yoke, RACI diagrams, statistical multiple linear regressions, risk management, data sampling, computer simulation, control charts, correlations, value stream mapping, variation analysis, Taguchi analysis, total quality management, DMAIC, TQM total quality management, histograms, TRIZ, and process charting. It is common for manufacturing specialists in Six Sigma to engage in benchmarking activities where they try to duplicate the best practices of non-competing organizations in order to find the maximum improvements for processes of interest.

Business schools, such as Harvard University, use case studies in Operations Management courses to teach project management and change management with six sigma as the guiding basis. The idea of optimizing a business process by measuring and then improving the performance of individual steps in a feedback loop is a type of robust change management that can be used to optimize not just manufacturing, but marketing and other business functions as well.

The theory of constraints is a related topic. The certification requirements for the six sigma methodology are explained in the many six sigma training courses available. The entire idea is to teach practitioners how to collect data that will enable them to measure and then eliminate defects in the operational performance of some process in question, which does not have to be manufacturing.

The whole idea of the tools or technique is encapsulated in DMIC: define the issue, measure the performance of the process involved, analyze the data and improve the process. The name "six sigma" comes from six standard deviations from the mean of a statistical process, which translates into defect rates below 3.4 defects per million occurrences of the process in question which is usually a continuous or batch production technique.