{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

Some Final Thoughts on DOE—for Everyone

It’s all in the planning

Davis Balestracci
Mon, 10/17/2016 - 14:21
  • Comment
  • RSS

Social Sharing block

  • Print
  • Add new comment
Body

Client A came to me for a consultation and told me upfront his manager would allow him to run only 12 experiments. I asked for his objective. When I informed him that it would take more than 300 experiments to test his objective, he replied, “All right, I’ll run 20.”

ADVERTISEMENT

Sigh. No, he needed either to redefine his objectives or not run the experiment at all.

I never saw him again.

Client B came to me with what he felt was a clearly defined objective. He thought he just needed a 10-mintue consult for a design template recommendation. It actually took three consults with me totaling 2 1/2 hours because I asked similar questions to those required for planning the experiment I wrote about in my column from September 2016.

During the first two consults, Client B would often say, “Oh... I didn’t think of that. I’ll need to check it out.” He eventually ran the experiment, came to me with the data, and asked, “Could you have the analysis next week?” I asked him to sit down and was able to finish the analysis (including contour plots) in about 20 minutes.

 …

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 darrelswift on Mon, 10/17/2016 - 09:15

What does DOE stand for in this instance?

Nice article, but not sure what DOE stands for in this instance

I've found it's a good practice to include what the acronym means the first time it's used and then use the acronym later, especially for any professional document.

DOE does not appear to mean Department of Energy or Education... maybe "Depending on Experience"... but not real sure. Maybe something related to operations.

Thanks again for the nice article, but I spent too much time trying to figure out what the acronym might stand for.

Darrel

  • Reply

Submitted by Quality Digest on Mon, 10/17/2016 - 09:33

In reply to What does DOE stand for in this instance? by darrelswift

Good catch

Nice catch. We have now spelled out "design of experiments" in first reference in the article. We don't do that in headlines but we normally catch those in the actual article. Thanks
  • Reply

Submitted by Stevenwachs on Mon, 10/17/2016 - 09:40

Using Standard Deviation of Process to estimate sample size

I believe the relevant standard deviation to be concerned with (when calculating the number of replicates), is that due to experimental error.  That is, the standard deviation among replicate measurements.  This is often much less than the typical process variation we might see assuming, we are following good experimental practices (one operator, single lot of material, or using blocking and covariates to manage variation due to these nuisance sources in the experiment).  Of course it's possible that experimental error could be more than normal process variation if the going through the various setups result in unintended variation.

  • Reply

Submitted by Davis Balestracci on Mon, 10/17/2016 - 11:39

In reply to Using Standard Deviation of Process to estimate sample size by Stevenwachs

Which variation to use?

Thanks for commenting, Steven.  I see what you mean, BUT...what happens when you try to take your results from a tightly controlled experiment into the real world environment, i.e., multiple operators and lots of material that combine at random? That's the REALITY of implementation and cannot be controlled.

A more robust approach might be judicious blocking of these nuisance (random, but very real) factors.  The resulting variation would be more than your approach but more realistic and not as bad as not leveraging the power to block them -- control charts managing the process would detect special causes among those factors with the appropriate variation "yard stick."  This variation is also not as naively low as controlling factors that are realistically uncontrollable.

The result you get from such a design is good only for your specific designed conditions, i.e., you have the result for THIS specific operator for THIS specific lot (enumerative).  How does that help you?  What is your theory about putting this result in the real world and not a lab?

As W. Edwards Deming always asked, "What can you predict?"  How robust is your result?  And this gets into the question, How is variation going to manifest in your results (analytic), i.e., multiple operators and multiple lots and factors you didn't even envision affecting your result?  Control charts are the ways to shed insight on these factors and increase your degree of belief in your study's validity.

Davis

  • Reply

Submitted by Davis Balestracci on Mon, 10/17/2016 - 11:42

Reply to Steven Wachs's Comment

See below...

  • 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