Browse Definitions:

Six Sigma: Glossary

black belt
Leaders of teams responsible for measuring, analyzing, improving and controlling key processes that influence customer satisfaction and/or productivity growth. Black Belts are full-time positions.

The state of stability, normal variation and predictability. Process of regulating and guiding operations and processes using quantitative data.

control chart
Monitors variance in a process over time and alerts the business to unexpected variance which may cause defects.

CTQ: critical to cqality (Critical "Y")
Element of a process or practice which has a direct impact on its perceived quality.

customer needs or expectations
Needs, as defined by customers, which meet their basic requirements and standards.

Sources of customer irritation. Defects are costly to both customers and to manufacturers or service providers. Eliminating defects provides cost benefits.

defect measurement
Accounting for the number or frequency of defects that cause lapses in product or service quality.

(Design for Six Sigma) - A systematic methodology utilizing tools, training and measurements to enable us to design products and processes that meet customer expectations and can be produced at Six Sigma Quality levels.

DMAIC (Define, Measure, Analyze, Improve and Control) - A process for continued improvement. It is systematic, scientific and fact based. This closed-loop process eliminates unproductive steps, often focuses on new measurements, and applies technology for improvement.

green belt
Similar to Black Belt but not a full-time position.

master black belt
First and foremost teachers. They also review and mentor Black Belts. Selection criteria for Master Black Belts are quantitative skills and the ability to teach and mentor. Master Black Belts are full-time positions.

Pareto diagram
Focuses on efforts or the problems that have the greatest potential for improvement by showing relative frequency and/or size in a descending bar graph. Based on the proven Pareto principle: 20% of the sources cause 80% of any problems.

process mapping
Illustrated description of how things get done, which enables participants to visualize an entire process and identify areas of strength and weaknesses. It helps reduce cycle time and defects while recognizing the value of individual contributions.

root cause analysis
Study of original reason for nonconformance with a process. When the root cause is removed or corrected, the nonconformance will be eliminated.

Six Sigma A vision of quality, which equates with only 3.4 defects per million opportunities for each product or service transaction. Strives for perfection.

statistical process control
The application of statistical methods to analyze data, study and monitor process capability and performance.

tree diagram
Graphically shows any broad goal broken into different levels of detailed actions. It encourages team members to expand their thinking when creating solutions.

A change in a process or business practice that may alter its expected outcome.

This glossary originally appeared on the General Electric Web site and is reprinted here with permission.

This was last updated in September 2006

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