{domain:"www.qualitydigest.com",server:"169.47.211.87"} Skip to main content

User account menu
Main navigation
  • Topics
    • Customer Care
    • FDA Compliance
    • Healthcare
    • Innovation
    • Lean
    • Management
    • Metrology
    • Operations
    • Risk Management
    • Six Sigma
    • Standards
    • Statistics
    • Supply Chain
    • Sustainability
    • Training
  • Videos/Webinars
    • All videos
    • Product Demos
    • Webinars
  • Advertise
    • Advertise
    • Submit B2B Press Release
    • Write for us
  • Metrology Hub
  • Training
  • Subscribe
  • Log in
Mobile Menu
  • Home
  • Topics
    • 3D Metrology-CMSC
    • Customer Care
    • FDA Compliance
    • Healthcare
    • Innovation
    • Lean
    • Management
    • Metrology
    • Operations
    • Risk Management
    • Six Sigma
    • Standards
    • Statistics
    • Supply Chain
    • Sustainability
    • Training
  • Login / Subscribe
  • More...
    • All Features
    • All News
    • All Videos
    • Contact
    • Training

‘Control Charts! They Make the Blind Hear and the Deaf See!’

Once again, I find myself appreciating Deming’s hatred of statistical hacks

Davis Balestracci
Tue, 07/14/2020 - 12:03
  • Comment
  • RSS

Social Sharing block

  • Print
  • Add new comment
Body

“With data from an epidemic there is no question of whether a change has occurred. Change is everywhere. The question is whether we are getting better or worse. So while the process behavior chart may be the Swiss army knife of statistical techniques, there are times when we need to leave the knife in our pocket, plot the data, and then listen to them as they tell their story.”
—Dr. Donald J. Wheeler

I agree with Dr. Wheeler’s comment about process control charts. Yet, I’m seeing far too many of them being inappropriately used as naïve attempts to interpret the mountains of questionable Covid-19 data being produced. I’ve done a few charts myself out of curiosity but none that I feel are worth sharing. Dr. Wheeler’s two recent, excellent Quality Digest articles have been the sanest things written—with nary a control chart in sight.

 …

Want to continue?
Log in or create a FREE account.
Enter your username or email address
Enter the password that accompanies your username.
By logging in you agree to receive communication from Quality Digest. Privacy Policy.
Create a FREE account
Forgot My Password

Comments

Submitted by Anonymous (not verified) on Tue, 07/14/2020 - 11:39

Three Monkeys

The use of "Percent Conformance to Goal" takes the data far out of context.  What exactly is being measured? Percent of what? Are the percentages calculated based on rational subgroups? 

Shouldn't a run chart be based on actual individual measurements?

  • Reply

Submitted by knowwareman on Tue, 07/14/2020 - 16:09

Control Charts put the C in DMAIC

Far too many improvement projects fail to put the Control phase into operation, resulting in the loss of the improvement.

We can haggle about run charts vs control charts, but if improvers are doing neither, it's irrelevant.

Line and bar charts of performance are the dumb and dummer of improvement charts. If you aren't willing to use control charts to monitor performance after improvement, don't bother with improvement.

Control chart software is very affordable. Just buy some. Start using the tools of quality. They might surprise you.

  • Reply

Submitted by Omar Gustavo Vázquez (not verified) on Tue, 07/14/2020 - 18:29

Excellent and very intelligent

As a teacher of SPC I found your article very usefull

I found your ideas very clear and easy to understand

Many thanks

  • Reply

Submitted by DAVID (not verified) on Tue, 08/18/2020 - 11:37

Control Charts

The first step is to know something about the data you desiire to analyze, i.e. was it generated by the same process? I too have seen may of the missteps fostered by software, it will do what you ask of it even if the ask is nonsensical. The humble time series chart and a histogram are a great way to begin the exploration.

  • Reply

Add new comment

Image CAPTCHA
Enter the characters shown in the image.
Please login to comment.
      

© 2025 Quality Digest. Copyright on content held by Quality Digest or by individual authors. Contact Quality Digest for reprint information.
“Quality Digest" is a trademark owned by Quality Circle Institute Inc.

footer
  • Home
  • Print QD: 1995-2008
  • Print QD: 2008-2009
  • Videos
  • Privacy Policy
  • Write for us
footer second menu
  • Subscribe to Quality Digest
  • About Us
  • Contact Us