Dear Experimenter,

Here’s a fresh set of answers to frequently asked questions (FAQs) about design of experiments (DOE); plus, timely alerts for events, publications, and software updates. Check it out!

Please let me know what you learned from this issue: I’d really appreciate hearing from you! Address your questions and comments to me at

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Mark J. Anderson, PE, CQE
Principal, Stat-Ease, Inc.

P.S. Quote for the month:
An astounding assertion about the value of data.
(Page down to the end of this e-zine to enjoy the actual quote.)


Vol. 20, No. 4 - July/Aug 2020

Business Alert
Stat-Ease re-energized by Vela Software & new management team

Software Alert
Version 12.0.10 of Design‑Expert® released

Defining terms: “ruggedness” vs. “robustness”

Webinar Alert
Multiple Response Optimization Unveiled

Info Alert
DOE achieves a huge success for biotechnology

Workshop Alert
Distance-Learning: master DOE at your own desk

StatsMadeEasy Blog
My wry look at all things statistical and/or scientific with an engineering perspective. Also, see the Stat-Ease blog for tips on making DOE easy. For example, a recent posting provides a wrap up on the 2020 Online DOE Summit. Take a look!
Stat-Ease re-energized by Vela Software and a new management team
I am pleased to announce that Stat-Ease is now a part of Vela Software via its Tecplot subsidiary. Our design of experiments (DOE) software fits in nicely with Vela’s growing portfolio of engineering and analysis tools. We will continue to operate as a stand-alone, independent business unit, committed to superb sales, statistical, and technical support.

This change in ownership allows for a transition from my long-time partner Pat Whitcomb and myself to a new management team led by Martin Bezener, our new President and CTO, working with Hank Anderson, VP of Software Development for our premier DOE-dedicated Design-Expert® software, and Cathy Hickman, VP Finance and Operations. To make this transition seamless for all of you in our Stat-Ease community, Pat and I will continue working part-time. Expect great things to come with the backing of Vela and Martin’s leadership. See more details about the ownership change in this press release.
Version 12.0.10 of Design-Expert Software Released
Current Design-Expert v12 (DX12) users will do well by updating to 12.0.10 via Help from within your installed program. View the changelog for details on the changes—mainly maintenance items. If you want to receive notice when an update becomes available, go to Edit on the main menu of your program, select Preferences and, within the default General tab, turn on (if not already on by default) the “Check for updates on program start” option. (This alert feature is not available in network versions.)
If you remain mired in an obsolete version or are not yet a user of Design-Expert, click here for the highlights on what’s new in DX12 (plus more details on added features via this link). Then, assuming you like what you see, follow the FREE TRIAL link for a 30-day tryout, or buy it directly—taking advantage of upgrade pricing if eligible.
Defining terms: “ruggedness” vs. “robustness”

Original question from a 2020 DOE Summit Attendee:
"Your 'Know the SCOR' talk* recommended 'ruggedness' testing for confirming DOE discoveries: Does this differ from 'robustness' studies?”
*View the recording for “Know the SCOR” (and other talks) by clicking the title on the 2020 Online DOE Summit Agenda.

The terms "ruggedness" and "robustness" get interchanged by most, that is, they are considered synonymous. However, whereas ruggedness can be tested via a low-resolution III two-level factorial such as a Plackett-Burman design, to really get a feel for robustness I recommend using a response surface method (RSM) in conjunction with tools for propagation of error (POE) provided by Design-Expert software*. Using RSM/POE you map the “flats”—regions that remain relatively unaffected by variation transmitted from factor variations. Therefore, robustness implies a more profound level of knowledge than ruggedness. But, bottom line, I favor ruggedness tests for their simplicity—fewer levels of each factor, more of them, and likely in less runs than a robustness RSM.

*From within Design-Expert, see Help, Tutorials, Response Surface (pt 3) for a demonstration of POE. For the methodology of POE refer to my iSixSigma article (co-authored by Pat Whitcomb) on Reducing Variability with DOE.
(Learn more about strategy of experimentation by attending the next distance-learning presentation of Modern DOE for Process Optimization.)
“Multiple Response Optimization Unveiled”
On Tuesday August 18 at 10am USA Central Daylight Time, Stat-Ease Consultant Shari Kraber will present a free webinar on “Multiple Response Optimization Unveiled”. She will demonstrate Design-Expert’s powerful tools for searching out sweet spots where you can meet all your requirements based on DOE-model predictions. Register here to attend the enlightening talk live and/or for notification of the recording being posted.
DOE achieves a huge success for biotechnology
This case study demonstrates the power of multifactor DOE versus the traditional scientific method of one-factor-at-a-time (OFAT) experimentation. Via a Design-Expert custom-optimal-design that cut the number of factorial runs by half, a Stat-Ease-trained biochemist achieved his experimental mission in a matter of weeks, rather than the months required by OFAT. Furthermore, the DOE produced a far more comprehensive mapping of process conditions, which provides great value for further improvements. See the case study here.
New distance-learning options to master DOE from the comfort of your own desk—Introductory-pricing and early-bird deals end soon, so sign up now!
You can do no better for quickly advancing your DOE skills than attending a Stat-Ease workshop. Our expert instructors provide you with a lively and extremely informative series of lectures interspersed by valuable hands-on exercises. Enroll at least 4 weeks prior to the date so your place can be assured—plus get a 10% “early-bird” discount. See this web page for complete schedule and site information on all Stat-Ease distance-learning workshops. To enroll, scroll down to the workshop of your choice and click on it, or email our Lead Client Specialist Rachel Poleke at If spots remain available, bring along several colleagues and take advantage of quantity discounts in tuition. Or, consider bringing in an expert from Stat-Ease to teach a private class at your site.*
*Once you achieve a critical mass of about 6 students, it becomes very economical to sponsor a private workshop, which is most convenient and effective for your staff. For a quote, email
“Data are profoundly dumb.”
—For the provenance and interpretation of this controversial statement, see this StatsMadeEasy blog post.
Stat-Ease, Design-Expert and Statistics Made Easy are registered trademarks of Stat-Ease, Inc.

Acknowledgements to contributors:
Students of Stat-Ease training and users of Stat-Ease software
Stat-Ease consultants: Pat Whitcomb, Martin Bezener, and Shari Kraber
Stat-Ease programmers: Hank Anderson, Joe Carriere, and Mike Brownson
Stat-Ease business staff: Cathy Hickman, Greg Campbell, and Rachel Poleke
—who provide such supreme support!

Circulation: Over 7500 worldwide
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