Quality Management Methods in Six Sigma

Projects following the Six Sigma approach to quality and reduction of waste will use two fundamental methodologies, each comprised of five different cycles, or phases, defining the project. These methods are called DMAIC and DMADV.

The DMAIC and DMADV acronyms are the quality management cornerstones of the Six Sigma business philosophy which is intended to refine and improve the quality of yields, while simultaneously identifying and eliminating the basis for errors.

DMAIC Project Methodology

DMAIC is an acronym for:

• Defining the problem
• Measuring vital aspects of the process
• Analyzing relevant information to examine cause/effect relationships
• Improving the process using data analysis
• Controlling the future process in order to eliminate potential errors

This methodology is always applied to processes which are already established but are experiencing issues that cause delay, quality reduction, and a skewed pattern in cost/benefit analyses. If this occurs in an organization, a team of qualified individuals are assembled whose job it is to search, augment, and eventually eliminate the cause or causes of whatever is producing the defect by using the DMAIC system.

DMADV Project Methodology

DMADV is an acronym for:

• Defining goals designed to fulfill customer demands
• Measuring and identifying characteristic CTQ's (critical to quality)
• Analyzing data to create and design alternatives
• Design and optimize details (this may need simulations)
• Verifying and implementing the process of an error-free production

In contrast to DMAIC, this methodology is predominantly applied to inventing new products or process procedures and may not work well on an established product or process. However, someone not trained in Six Sigma may have trouble understanding the difference between DMAIC and DMADV methodology, and this is where a certified expert would need to direct the implementation of either strategy.

Other Quality Management Tools

Many of the quality management devices utilized by Six Sigma methodology are also employed in other analytic processes outside this specific quality improvment methodology. Some of these more commonly used tools include:

• Cost-benefit analysis
• TRIZ 
• Histograms 
• ANOVA 
• Ishikawa diagrams   
• Regression analysis

The majority of these tools are statistical in nature, and are meant to quantitatively illustrate the level of performance that a process is currently attaining. ‘6 Sigma’ is said to be achieved when the process does not generate in excess of "3.4 defects per million opportunities". Within this specific statistical terminology, a defect is anything that does not conform to customer satisfaction. An opportunity is the sum of chances a defect may contain.

Overall, Six Sigma is a very detailed and specific methodology requiring knowledge of statistical significance and diagnostic implementation of accrued data. In this way, defective processes are transformed and errors are potentially prevented before they occur.


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