Last month’s column, “The Top 10 SPC Mistakes,” outlined five mistakes to avoid when building a successful statistical process control (SPC) system. Here they are:

10. Training everyone
  9. Charting everything
  8. Segregating control charts from manufacturing
  7. “Pinching” the SPC coordinator
  6. Using SPC because it’s a “good thing to do.”

Now, here are the remaining five SPC mistakes:

5. Using SPC as a data collection exercise
I frequently encounter SPC systems that look like this: Throughout a shift, an operator periodically takes measurements from some parts. He writes them down on a piece of paper. At the end of the shift (or the week), an administrative support person collects the papers from the operators. The next day or week, the support person takes the papers, opens some spreadsheet software and enters the numbers that had been written down. Control charts are printed out and then placed into company mail and delivered to a process engineer who typically exclaims, “Wow, we had something go out of control last week.”

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