11.17.2015

Can Design of Experiments (DOE) Be Simplified?

Mark J. Anderson and Patrick J. Whitcomb just published the the third edition of their innovative book, DOE Simplified: Practical Tools for Effective Experimentation, and I had the chance to speak with Mark about its content. I asked him: "Nothing could be simpler than the traditional scientific method so why abandon this old-school approach for experimentation?" Here is Mark's complete answer:

It is true that that the scientific methods we all learned in school could not be any easier -- simply hold everything in your system constant other than changing only one factor at a time (OFAT). For example, It works very well for demonstrating scientific principles in a chemistry class. For the following two reasons, however, the OFAT method falls flat for real-world experiments:

1. It cannot detect interactions of factors (e.g., the combination of time and temperature burning the food you cook in your kitchen).
2. It is very inefficient.

I explain why in this very brief two-part primer -- Trimming the FAT out of Experimental Methods and No-FAT Multifactor Design of Experiments.

Now that you understand why OFAT must be abandoned, you are ready to take the next step (i.e., mastering the multifactor test methods of design of experiments -- DOE -- by reading our book). We start you off easy with several chapters with some basic statistics and simple comparative experiments. Then in Chapters 3 through 5, we explain how to use the primary tool for DOE: two-level factorials. These designs are excellent for screening many factors to identify the vital few. They often reveal interactions that would never be found through OFAT methods. Furthermore, two-level factorials are incredibly efficient, producing maximum information with a minimum of runs. Most important, these designs often produce breakthrough improvements in product quality and process efficiency.

Continuing on from there, the book fills in all the gaps remaining for getting an effective grasp on the powerful tools for multifactor testing. We cap it all off with a new chapter written especially for 3rd Edition -- It reveals a middle way, called “split plot,” between OFAT and DOE when experimenters are confronted with factors that are very hard to change.

By the way, this new edition vaults the book into a format amenable to electronic users as it's available in many eBook formats. Now, web-connected experimenters around the globe can read DOE Simplified. Furthermore, mainly from the hard work of my colleagues at Stat-Ease, we accomplished a re-launch of the “Launch Pad” -- a series of interactive web-based lectures that cover the first several chapters of the book. The Launch Pad e-learning class provides momentum that propels readers through the DOE Simplified text. Contact workshops@statease.com for more information about the Launch Pad. 

Have any readers here used the new edition of DOE Simplified: Practical Tools for Effective Experimentation? Has it been helpful? Do you agree with Mark Anderson's points? 

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