Six Sigma Glossary

This Six Sigma Glossary provides an overview of commonly used Six Sigma terms and tools.

CAPABILITY INDICES            

A mathematical calculation is used to compare the process variation to a specification.  Examples are Cp, Cpk.  Used to compare processes across businesses

CHAMPION                           

An upper-level business leader who identifies selects and charters continuous improvement projects and supports the delivery thereof

CONTROL PLAN                    

A process control document that lists all of the elements required to control variations in a process under study or in routine operation

CONTROL SPECIFICATIONS   

Customer requirements for a process under study or in routine operation

COST OF POOR QUALITY (COPQ)  

The cost associated with providing poor quality products or services.  The cost of not producing first quality for the Customer the first time and every time

CUSTOMER                            

People process or equipment that receives products or services from you as a supplier. These may be internal of external customers

DEFECT                                  

Any characteristic that deviates outside of customer requirements

DEFECT PER MILLION (DPM)   

A quality metric often used in the Lean Six Sigma process. It is calculated by the number of defects observed divided by the number of opportunities for defects compared to 1 million units

DESIGN OF EXPERIMENT (DOE)          

A formal, proactive method for experimenting with Xs and Ys. It involves concepts such as factors, levels, center points, blocking, and replications

GAGE ACCURACY                 

The average difference observed between a gage under evaluation and a master gage when measuring the same parts over multiple readings

GAGE REPEATABILITY          

A measure of the variation observed when a single operator uses a gage to measure a group of randomly ordered (but identifiable) parts on a repetitive basis

GAGE REPRODUCIBILITY      

A measure of average variation is observed between operations when multiple operators use the same gage to measure a group of randomly ordered (but identifiable) parts on a repetitive basis

GREEN BELT (GB)                 

Lean Six Sigma role is similar in function to Black Belt but the length of training and project scope are reduced

HISTOGRAM                          

Vertical display of population distribution in terms of frequencies

PROCESS INPUT VARIABLE 

The vital few input variables called “X’s”

PROCESS OUTPUT VARIABLE

The output variable, called “Y”.  Usually only one Y is studied at a time

MASTER BLACK BELT (MBB)

A person who is an “expert” on Lean Six Sigma techniques and on project implementation.  Master Black Belts play a key  role in training and coaching of Black and Green Belts

MEASUREMENT SYSTEMS (MS)

Means of evaluating a continuous or discrete measurement system with the intention of discovering how “good” or “bad” the measurement systems are

MINITAB                                

Statistical software package that operates in a Windows environment and is the main statistical package used by students

MULTI-VARI ANALYSIS        

(Inferential Statistics) Passive data collection method used to display the variation within parts,  machines, or processes between machines or process parts, and overtime

NORMAL DISTRIBUTION      

A continuous, symmetrical density function characterized by a bell-shaped curve

PROBABILITY                        

The chance of an event happening or condition occurring by pure chance

PROCESS                                

The method in which something is manufactured or serviced

PROCESS MAP                      

A step-by-step pictorial sequence of a process showing process inputs, process outputs, cycle time, decision points, rework operations, and inspection points

PROCESS OWNER                 

is the individual who accompanies the project work and assists with the implementation of the solution. This individual owns the process and ensures improvements implemented are sustained and continuously improved

PROCESS SPREAD                 

The range of values that a given process characteristic displays; this term most often applies to the range but may also include the variance.  The spread may be based on a set of data collected at a specific point in time or may reflect the variability across a given period of time