Bringing design of experiments (DOE) to England might be likened to delivering coals to Newcastle, but that's what three U of M IT alumni1 accomplished via their company, Stat-Ease, Inc., when they displayed their Design-Expert® software,2 at the international Industrial Statistics in Action Conference at Newcastle University. Attendees from the United Kingdom, Europe and worldwide responded very enthusiastically. As testimonial, statisticians from SmithKline Beecham Pharmaceuticals put up a poster saying that easy-to-use software, specifically Design-Expert, must be made available to all experimenters to foster use of DOE.3
The irony of this trans-Atlantic software success is that DOE methods came to the USA from England. Sir Ronald Fisher, a distinguished British statistician, developed the basic tools while at Rothamsted Agricultural Station in the 1920's. He published the seminal "Design of Experiments" in 1935. During this period, most of the DOE work occurred (literally) in the field of agriculture. For example, in a pioneering study, researchers from the University of Minnesota made use of the statistical tools developed by Fisher to evaluate different types of barley.4 They randomly applied the various treatments within several blocks of land at various agricultural stations around the state. After removing the block differences and accounting for natural variability in yields, they saw statistically significant advantages to growing certain types of barley. The design used for this one-variable experiment is called a randomized block.
During World War II, a more sophisticated form of DOE, called factorial design, became a big weapon for speeding up industrial development for the Allied forces. These designs can be quite compact, involving as few as two levels of each factor and only a fraction of all the combinations, and yet they are quite powerful for screening purposes. After the war, a statistician at Imperial Chemical, George Box, described how to generate response surfaces for process optimization.5 From this point forward, DOE took hold in the chemical process industry, where factors such as time, temperature, pressure, concentration, flow rate and agitation are easily manipulated. Later, Box co-authored a textbook6 that formed the basis for the first DOE program by Stat-Ease--Design-Ease® software.
The principals of Stat-Ease learned DOE while working together at General Mills in its chemical research laboratory only a few miles north of the University campus. They recognized an opportunity when IBM came out with its original PC: The methods described by Fisher and Box could be incorporated in a menu-driven computer program that would make DOE easy for non-statisticians. By then, the chemical division of General Mills had been sold to Henkel of Germany. For various reasons, such as Minnesota being the "Siberia of the US," the new owners decided to disband all operations in the area.
At this juncture Pat Whitcomb decided to devote full time to Stat-Ease, a DOE software venture Pat started on a moonlighting basis in 1982. Pat incorporated Stat-Ease in April of 1985, and with programming help from his colleague Tryg Helseth, completed development of Design-Ease. In June of 1985 they sold their first copy, but sales didn't take off until 1987, when a professor from the University of Minnesota7 described Design-Ease as "incredibly easy to use" in a widely-read review of DOE software. With profits now rolling in, Stat-Ease could afford to bring Tryg on as a full-time programmer and hire another former colleague, Mark Anderson, as the business manager.
In 1988, the company released its first version of Design-Expert, which provided the tools for response surface methods (RSM) for process optimization. This package complemented Design-Ease. Design-Expert also provided innovative statistical tools for optimizing mixtures—a big attraction for users in the chemical process industries. With this product line extension, sales grew at a healthy rate and Stat-Ease added many new employees to handle orders, provide statistical help and program new features.
A major milestone occurred in 1996: Stat-Ease incorporated all of the features of Design-Ease into Design-Expert version 5 and translated it all to the graphical user interface of Windows. By then its user base approached six figures, so the demand for upgrades stimulated sales and allowed further hiring of programmers and other personnel. They contributed to development of version 6.0 of Design-Expert software released in 2000, and rounded out the array of designs, including the ability to combine mixture components with process factors. Design-Expert (now on version 8) is widely recognized as one of most powerful programs for doing DOE, yet is easy enough for use by non-statisticians who do industrial experimentation. Design-Expert is also used as a teaching tool by colleges and universities. It even comes packaged with one of the leading textbooks for DOE.8
The Stat-Ease mission is "Statistics Made Easy." This would be mission impossible without proper education. Unfortunately, most scientists and engineers get very little statistical training in college. Stat-Ease fills the gap with a variety of computer-intensive short courses from "Experiment Design Made Easy," the most popular workshop, up to advanced sessions on optimization and beyond. Aided by a stable of in-house and contract consultants, Pat and Mark teach hundreds of technical professionals the tools of DOE at dozens of workshops worldwide. For those who need help getting off the ground, they have authored two non-academic books that make DOE and response surface methodology (RSM) as easy as possible for non-statisticians.9
At the other end of the spectrum, the statisticians at Stat-Ease have been active in developing new tools for design of experiments. Professor Kinley Larntz from the School of Statistics at the U of M advised Stat-Ease from the beginning through 1999. He and Pat won the Shewell Award for best presentation at the prestigious Fall Technical Conference (FTC) in 1998.10 (This is an important forum for DOE that's co-sponsored by the Chemical and Process Industries Division and the Statistics Division of the American Society for Quality (ASQ) and the Section on Physical and Engineering Sciences from the American Statistical Association (ASA).) Professor Gary Oehlert, also from the U of M and an author on the subject of DOE,11 now provides statistical advice to Stat-Ease. He gave a well-attended presentation12 at the 2000 FTC held in Minneapolis (all roads lead to Minnesota!). In 2007 Pat and Gary won the Shewell Award for best presentation at the 2006 Fall Technical Conference. In 2011 Pat and Stat-Ease statistical consultant Wayne Adams won the Shewell Award for best presentation at the 2010 Fall Technical Conference—the 3rd time for Pat!
Stat-Ease now employs about more than a dozen employees at its headquarters in Minneapolis. The company is represented by consultant/resellers at major cities throughout the US and in most of the developed nations. The future looks very bright for Stat-Ease here in the center of North America, throughout the continent, and across the Atlantic to England and Europe. The next region to be conquered will be on the far side of the Pacific. Stat-Ease already has a foothold there via its connections to US-based multinationals, one of whom commissioned Pat to teach at its technical facilities in Japan, Taiwan and Korea. India has become a new major area of activity for DOE in the pharmaceutical field. It's now just a matter of time for the word to spread throughout the rest of the Far East on how easy DOE can be with Stat-Ease software.