Background and Motivation
In January 1994, the Statistics Division (Britz et al, 1996) adopted a tactical plan to Enable Broad Application of Statistical Thinking. The division developed a definition of Statistical Thinking which was published by Quality Press in 1996. That definition is identical to the principles listed above as the basis for Statistical Thinking. As the Past Chair of the division, I am motivated to promote the use of Statistical Thinking.
Why does the Statistics Division assign such a high priority to Statistical Thinking? Why doesn’t the Statistics Division simply emphasize statistical methods such as SPC, DOE and regression analysis? The answer is that the benefits of statistical methods are significantly improved by their use in the context of Statistical Thinking.
Brtiz el (2000) point out that Statistical Thinking incorporates key concepts from several improvement methodologies such as Six Sigma, Total Quality Management (TQM) and systems thinking. These key concepts include:
- A holistic approach to improving the system
- Viewing work as a process
- Using data to guide decisions
- Recognizing and responding wisely to variation
Clearly, Six Sigma uses Statistical Thinking. Benbow and Kubiak (2005) state on page 2:
- “Understanding and improving processes is a key part of every Six Sigma project.”
- “Six Sigma focuses on reducing process variation and enhancing process control, ”
Six Sigma uses a measure of variation, illustrated in the figure, as its overall measure of project success. That is, for the distribution of the key quality characteristic, the distance from its mean to the closest specification limit (LSL or USL) measured in standard deviation (sigma) units.
In my opinion, Statistical Thinking is a crucial concept in Six Sigma. We will see later that a customer focus is inherent in Statistical Thinking because a process includes its customer.
References
- Britz, G. et al. (1996). Statistical Thinking, ASQ Statistics Division Special Publication.
- Britz, G. et al. (2000). Improving Performance Through Statistical Thinking, ASQ Quality Press.
- Benbow, D. W. and T. M. Kubiak (2005). The Certified Six Sigma Black Belt Handbook. Milwaukee, Wisconsin, ASQ Quality Press.
