Anticlue

As we have stated variation is a deviation from what typically happens in a process. Variation is essentially a defect. As we all know defects are bad evil, not really tolerated and show be made to disappear. Therefore the goal of Six Sigma is to reduce the variations or defects within a process so that the process consistently meets our customers expectations and requirements.

There are two main categories of variation – special cause and common cause.

• Special cause variation results from sources that are not inherent to the process, like the project manager is out sick for the production deployment of the upgrade.
Common cause variation results from naturally occurring sources that are inherent to the process, such as the upgrade was completed by a newbie.

Now let’s say this upgrade really didn’t go too well. It maybe actually due to both: a special cause variation and a common cause variation. The project manger being out sick for the production deployment of the upgrade is a special cause. However having a newbie do the upgrade is inherent to IT process, and a common cause.

The question to ask is whether the variation is inherent or built into the process?

So as one is analyzing a process for variation what are the possible sources? Experience tells us there are five sources of variation:

• Materials – Materials are the physical elements in the process. For example materials can be a source of variation when for the data center there are two suppliers of servers or equipment.
• Methods – Methods are the techniques used to accomplish a task. A method can become a source of variation when one worker accidently applies the previous procedure to doing an operational task.
• Measures – Measures are the techniques to measure. For example if one measurement of time spent is based on duration, and another measurement of time spent is based on effort. Then there is variation when the measures are compared.
• Mother Nature – Mother nature is the environmental factors that create a variation in the process. For example a mudslide caused the building to close.
• People – People are a source of variation when they perform a task differently than they normally would, or differently from how everyone else is performing the task. For example, an experience colleague is worried about family issues, so he may not be as diligent and detailed oriented as normal.
  

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