Case Studies and White Papers

Optimize Your Process-Optimization Efforts

Published: December 1996
Authors: Mark Anderson, Patrick Whitcomb

What would you do it confronted with an "opportunity" to make a major change, involving many factors, but you need to do it quickly? The traditional approach to experimentation requires you to change only one factor at a time (OFAT). However, the OFAT approach doesn’t provide data on interactions of factors, a likely occurrence with chemical processes. An alternative approach called “two-level factorial design” can uncover critical interactions. This statistically based method involves simultaneous adjustment of experimental factors at only two levels, offering a parallel testing scheme that’s much more efficient than the serial approach of OFAT.

Publication: Chemical Engineering Progress

Published: May 1996
Authors: Mark Anderson, Patrick Whitcomb

Talk by Pat Whitcomb and Mark Anderson that was presented at the 50th Annual Quality Congress.

Publication: Conference

A Balancing Act: Optimizing a Product's Properties

Published: June 1994
Author: George Derringer

G.C. Derringer provides an easy-to-read explanation of the commonly used optimization function called desirability. When used as the final step in DOE, this function allows simultaneous optimization of multiple responses, resulting in the discovery of a group of optimal factor settings.

Publication: Quality Progress

Applying DOE to Microwave Popcorn

Published: July 1993
Authors: Mark Anderson, Hank Anderson

Design of experiments identifies which factors matter and which ones don't when microwaving popcorn, as well as helping find optimal settings.

Publication: Process Industries Quality

Analyzing Two-Level Factorials Having Missing Data

Published: January 1993
Authors: Kinley Larntz, Patrick Whitcomb

This presentation details and demonstrates a procedure that, despite missing data, allows the use of user-friendly, normal-probability plots for two-level-factorial effect selection.

Publication: Fall Technical Conference, St. Louis

Published: January 1992
Authors: Patrick Whitcomb, Kinley Larntz

A look at augmenting the usual probability plot effects with points representing pure error.

Publication: Conference

A Simple Comparative Experiment with Paper Clips

Published: January 1992
Author: Mark Anderson

Details and demonstrates a fun experiment to do at home or in class to build understanding of variation and how it can be handled with simple comparative designs. For teaching purposes it works best if each student breaks two brands of clips, thus providing data for a paired t-test, which blocks out variability due to the tester.

An updated version of paper-clip experiment is provided in the June 2009 Stat-Teaser posted at

Publication: Stat-Ease, Inc.