The term Six Sigma Methodology refers to a highly structured quality management program that relies on a disciplined data-driven approach for improving business processes. Once known as a methodology for eliminating product defects, Six Sigma has evolved into a robust management discipline that is widely used to improve not just manufacturing processes but also transaction- and service-oriented processes as well.

To achieve a Six Sigma level, a business process cannot have more than 3.4 defects per million opportunities for a defect to occur. In comparison, a Five Sigma operation can tolerate up to 233 defects per million while a Four Sigma operation can have over 6000 defects. By Six Sigma standards, any variation from customer specifications is considered a defect.

Essentially the Six Sigma Methodology and Six Sigma consulting is aimed at improving process quality by gathering and using highly detailed metrics to identity and drive out all process variations. It requires all business and manufacturing processes to be put through what is known as either a DMAIC process or a DMADV process.

DMAIC stands for Define, Measure, Analyze, Improve and Control. It is a quality improvement system for existing business processes that do not measure up to Six Sigma quality levels. The objective of the DMAIC process is to drive incremental improvements in existing business processes.

DMADV--for Define, Measure, Analyze, Design and Verify—on the other hand, is a program that is used to ensure that new processes and projects meet Six Sigma quality levels. Sometimes, an existing process that requires a major overhaul can also be run through a DMADV program.

Implementing the Six Sigma methodology can be a major challenge for corporations. Companies that do not have relatively sophisticated and mature quality management programs to begin with could find themselves needing to make major structural changes to accommodate the new methodology. The program can also require considerable investments in employee training and in making process tweaks.

For those who are willing to invest the resources, the time and the discipline, Six Sigma can yield significant returns in the form of improved product quality and substantially lower operational costs.

Companies which are unsure where to start, or do not have the skill-set needed to implement a Six Sigma project can always contract out their requirements to Six Sigma consultants. One big advantage that Six Sigma consultants bring to the table is the fact that they have skilled resources, the expertise and the experience to get a project launched much faster than a company would be able to on its own.