Dr.Ron's Insights: Statistics Roundtable-Raise Your Batting Average(2)

A strategy that works

Over the years, it has been recognized that experimentation is more effective when it is approached with a strategy in mind.

For any strategy to be effective, it must recognize that the design (or sequence of designs) should match the experimental environment.

Experimentation is sequential, and the DoE tools must be embedded in the strategy, linked and sequenced to guide the experimenter.

The sidebar, “Ignoring Sequence—An Example,” describes an experiment in which the sequential nature of experimentation was not considered, resulting in an ineffective and inefficient experimental program.

Poor planning is frequently the culprit. For instance, you may run out of time and money before you get to a useful answer.

An important variable may be missed because a well-thought-out experimental plan was not developed—often the result of a

desire to show results too quickly.

This experience leads to the following principles that can enhance experimental strategies:

• Plan ahead. Decide on the series of experiments that may be needed to satisfy the objective of the experimental program.
• Consider all factors. In the beginning, include (or at least consider) all factors (Xs) that may possibly be important. Recall the Pareto effect, which says the majority of the variation will be caused by a small subset of the factors. As you move through the experimentation, the important factors will be discovered and tested further in later experiments.
• Don’t spend all your resources on a single experiment. As mentioned earlier, an issue is rarely resolved in a single experiment.

A strategy that uses these principles was developed at DuPont in the 1960s and offered in public workshops in the 1970s. This strategy identifies three experimental environments: screening, characterization and optimization (SCO). The objective of each of the three phases and the designs
used are summarized in Table 1.

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Dr.Ron's Insights: Statistics Roundtable-Raise Your Batting Average(1)

Dr.Ron's Insights: Statistics Roundtable-Raise Your Batting Average(3)

About the author:
Ronald D. Snee, PhD is founder and president of Snee Associates, a firm dedicated to the successful implementation of process and
organizational improvement initiatives. He provides guidance to senior executives in their pursuit of improved business performance
using QbD, Lean Six Sigma, and other improvement approaches. Ron received his BA from Washington and Jefferson College and MS
and PhD degrees from Rutgers University. He is a frequent speaker and has published four books and more than 200 papers.

Next Update: Nov.27th