Causes of Variation

Exercise

Now think of some instances in your own work where outcomes vary, and why. Take one example and make a list for yourself of all the areas of variation and their potential causes.

Often we make snap judgements about the causes of variation, particularly those attributable to special causes. We have all made statements like:

• "It's that new operator..."
• "It's the new stuff from that supplier..."
• "It's those new widgets that have caused the problem..."

Variation is present in all inputs to the process, not only the people or materials. No matter how well in control a process is, its outputs will provide a distribution around a tartget, or ideal output.

But, variation is the voice not only of the process itself, but of each element within it. Only by understanding what the process is telling us will we arrive at the correct conclusions and make the right decisions.