One of the most useful diagnostic tools for understanding what is going on in a process is the statistical process control chart (SPC).  This is also a frequently misunderstood tool, and these misunderstandings lead to misdirected effort during a Six Sigma process, resulting in lost time and money. All the questions related to these foiled efforts boil down to this, “I used my software to make a control chart, but the chart looks all messed up.  Why doesn’t SPC work?” 

It does, if you avoid some common pitfalls.  So today, I am kicking off a few articles about these pitfalls that I hope will make your projects less frustrating and more efficient.

No Measurement System Analysis

In my experience, the most common error in doing SPC is not performing a measurement system analysis first.  This is an occurrence that calls for a real head thumping on the desk (yours, or maybe the person’s who didn’t do the study, if you can get away with it).

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