Compare and contrast the fundamental differences between spe

Compare and contrast the fundamental differences between special-cause variation and common-cause variation. Provide one (1) business process example of each variation to support your response.

Solution

Common cause variation are those uncontrollable aspects of the overall process. Sometimes it is referred to as “noise”. An example of this could be temperature or humidity in a manufacturing environment where you have no control over either variable. The common cause variation is measured when you get the process capability. Usually you will have all of the special cause variation controlled at this point.
Special cause variation are those variables that you can change, or eliminate, to improve your process. Anything that you can measure and control against the desired output is special cause variation.
This is a very simplified explanation, but I,ve found that keeping this part of the process simplified makes it easier to control. If you use the Six Sigma roadmap and tools, specifically the Cause and Effects matrix and the FMEA, you should know which variables are important to control, which ones you can control, and which ones you can’t.

Common-cause variation is characterised by

The outcomes of a perfectly balanced roulette wheel are a good example of common-cause variation. Common-cause variation is the noise within the system.

Walter A. Shewhart originally used the term chance cause. The term common cause was coined by Harry Alpert in 1947. The Western Electric Company used the term natural pattern. Shewhart called a process that features only common-cause variation as being in statistical control. This term is deprecated by some modern statisticians who prefer the phrase stable and predictable.

Special-cause variation is characterised by

Special-cause variation always arrives as a surprise. It is the signal within a system.

Walter A. Shewhart originally used the term assignable cause.^[3] The term special-cause was coined by W. Edwards Deming. The Western Electric Company used the term unnatural pattern.