Throughout years of mentoring and teaching aspiring quality professionals, I still review the Shainin techniques.
Dr. Dorian Shainin may not be well known to many of today’s quality professionals who have grown up using powerful computers. In an age prior to computer-assisted solutions, Shainin developed practical tools to help manufacturers solve problems, including those which, at the time, had been considered unsolvable.
For those with limited exposure to Shainin, it’s worth noting a few basics. Shainin received an aeronautical engineering degree from MIT in 1936 before going to work for Hamilton Standard, a division of United Aircraft Corp., now United Technologies Corp. As with many, his life changed significantly due to his war efforts when, through the lend-lease program, he became friends with Joseph M. Juran.
Shainin rose to national prominence with development of his Lot Plot which involved a statistical method for acceptance sampling in lieu of 100% inspection. He influenced the U.S. Navy to adopt his Lot Plot as a standard which was soon used by many industries. Shainin followed Joseph M. Juran, who had developed into a mentor, to become one of the very early quality consultants.
In time, Shainin founded his own company and worked with more than 900 different companies across many industries. He was responsible for developing more than 20 statistical engineering techniques that were the core of what came to be called the Shainin techniques or the Shainin system for quality and reliability improvement.
Shainin, like Juran who popularized “the vital few and trivial many” (also known as the Pareto Principle), came to realize that quality defects had an unequal frequency in that only a relative few accounted for most of the defects.
Shainin concluded that from the multitude of variables that could influence a significant change in an output, one cause-and-effect relationship had to be stronger or more significant than the others. This led to what he called the Red X, which he theorized was the primary cause of process and product problems.
His was a simpler and practical approach to problem-solving in the days prior to powerful computers. Shainin stressed “talking to parts” which consisted of swapping pairs of parts of functional and non-functional parts until the culprit was discovered. His claim was the defective part could be found within a dozen paired swaps.
After attending a workshop on the Shainin system, I became influenced by his techniques. I even adopted the philosophy of “be quiet and listen to the parts.” I’ve used this technique in many situations to find the answer to a problem. This allowed the focus to be on the offending part so not only was the product problem solved but working backwards the design or process could be improved to prevent recurrence.
With the Shainin method there was a certain degree of a theoretical step, but mainly it was to determine possible causes of a problem. This was accomplished by one or more techniques designed to determine root cause or the Red X.
As a quality engineer, I was part of a team addressing a perplexing problem of excessive noise from a particular gear train. It appeared non-randomly, but was troublesome because the root cause could not be pinpointed.
Using the Shainin approach, the noise was isolated to a set of gears. With the limited metrology sophistication at the time, all that was known is that all gears and shafts in question were compliant to engineer specifications.
After a few “swaps” of gears and shafts from noisy and non-noisy units, the team was able to identify the offending parts. To ensure that the root cause was isolated, the noise could be made to repeat. So the team was confident that, although the root cause itself wasn’t yet known, the offending part had been identified.
With design engineering help it was determined the root cause was a “stack-up” problem with engineering design tolerances. Design changes took care of the issue, and the problem disappeared! Was this highly statistical or sophisticated? Absolutely not, but the problem was solved relatively quickly.
Shainin also worked as a reliability consultant for the NASA Apollo Lunar Module. He developed new approaches for reliability assessment which led to zero failures in eleven manned missions and six moon landings. Further, when problems arose with the famous Apollo 13 mission, the Lunar Module brought the astronauts safely back to Earth.
American Society for Quality named Shainin a Fellow in 1952. He also received the ASQ Brumbaugh Award, the Edwards Medal, the Grant Medal and the Shewhart Medal—making him the first person to hold all five prestigious ASQ medals. ASQ made Shainin their 15th Honorary Member in 1996 and in 2004 created the Dorian Shainin Medal.
Next month, we will continue discussing Shainin’s approach to problem-solving. Even though his is a voice from the past, it still resonates.