For six sigma:

The first step on ensuring quality is to “Define” or gain understanding of the process by separating the process into its basic components so that they are easily understood (Input & Output). The use of flowcharts are common for this step.

The second step is to establish a measurement system that is reliable for the process so that you could “Measure” the current performance to detect problems (if any) and hence could also measure changes for improvement made to it.

The third step is to “Analyze” the process performance by using statistical techniques such as SPC, DOE, etc and hence pinpointing areas where improvement could be made.

The fourth step is to perform the necessary “Improve”ment based on your understanding of the process and also the insight given by the statistical analyzes made on step three above.

The fifth and last step, are establishing “Control” procedure to ensure that any improvement made will be maintained and not lost. Things like SOP are normally used for this purpose.

Obviously, in the past, there has been other quality initiative in place and the tools used in six sigma (statistics, graphs, etc) are also not new but six sigma really accumulate all those available tools and provide the well defined roadmap needed so that you could attack any process in a systematic way and accomplish your goal.

Hope this helps.

Six Sigma at many organizations simply means a measure of quality that strives for near perfection. Six Sigma is a disciplined, data-driven approach and methodology for eliminating defects (driving towards six standard deviations between the mean and the nearest specification limit) in any process — from manufacturing to transactional and from product to service.

The statistical representation of Six Sigma describes quantitatively how a process is performing. To achieve Six Sigma, a process must not produce more than 3.4 defects per million opportunities. A Six Sigma defect is defined as anything outside of customer specifications. A Six Sigma opportunity is then the total quantity of chances for a defect. Process sigma can easily be calculated using a Six Sigma calculator.

The fundamental objective of the Six Sigma methodology is the implementation of a measurement-based strategy that focuses on process improvement and variation reduction through the application of Six Sigma improvement projects. This is accomplished through the use of two Six Sigma sub-methodologies: DMAIC and DMADV. The Six Sigma DMAIC process (define, measure, analyze, improve, control) is an improvement system for existing processes falling below specification and looking for incremental improvement. The Six Sigma DMADV process (define, measure, analyze, design, verify) is an improvement system used to develop new processes or products at Six Sigma quality levels. It can also be employed if a current process requires more than just incremental improvement. Both Six Sigma processes are executed by Six Sigma Green Belts and Six Sigma Black Belts, and are overseen by Six Sigma Master Black Belts.

According to the Six Sigma Academy, Black Belts save companies approximately $230,000 per project and can complete four to 6 projects per year. General Electric, one of the most successful companies implementing Six Sigma, has estimated benefits on the order of $10 billion during the first five years of implementation. GE first began Six Sigma in 1995 after Motorola and Allied Signal blazed the Six Sigma trail. Since then, thousands of companies around the world have discovered the far reaching benefits of Six Sigma.