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Bruce Hamilton


When PDCA Meets Silos

Boundaries between production, inspection, and engineering obscure opportunities for process improvement

Published: Wednesday, July 21, 2021 - 11:02

PDCA—plan, do, check, act (or adjust)—is one of those acronymic concepts that regularly finds its way into lean discussions. Descended from Francis Bacon’s scientific method (hypothesis, experiment, confirmation), PDCA has become a ubiquitous catchword for business process improvement. From standardization and problem solving on the frontline to iterative product and process design to hoshin, this approach is the engine for continuous improvement.

But like many lean concepts, when layered over a traditional organizational structure, PDCA can fall far short of its promises.

My initial exposure to the concept, Shigeo Shingo’s Zero Quality Control: Source Inspection and the Poka-Yoke System (Routledge, 1986) offered an unusual, nontechnical insight into PDCA. Referring to the concept in the context of quality improvement as “informative inspection,” Shingo posed a couple of critical questions:
1. How rapid is the feedback?
2. Who is involved?

Traditional feedback loops were gated, according to Shingo, by a quality control function, a group of subject matter experts “enshrined on a lofty mountain” far away from the “production village.” Several outcomes of this approach were:
1. Checking (inspection) was a batch process, separate from production, with all of the batch’s attendant delays. Information was yesterday’s news by the time it reached the lofty mountain. Whatever conditions may have caused a nonconformance were lost in time.
2. The people doing the checking were remote from the workers, both physically and interpersonally. Division of labor became implicitly unequal: thinkers and doers.
3. The doers in the production village no longer had responsibility for quality and often no longer had even the capability to check.  

Regrettably, these outcomes noted by Shingo in 1985 are still commonplace today. As a consultant, I regularly observe long delays to setups caused by remote first-piece inspections and worse—forensic root cause analysis initiated long after defects are created. But worst of all, the folks closest to the problems are not at the table. When PDCA meets silos, it too becomes siloed. Information from production to QC flows through a semipermeable boundary, one-way at best and subject to bias and conjecture. Not a very favorable environment for problem-solving.

Similar boundaries between production and engineering also obscure opportunities for process improvement. In a social model where production workers are doers and engineers are thinkers, the most critical process information is often lost. An engineering manager once remarked to me, “If all employees were engineers, we wouldn’t need mistake-proofing.”

Shingo spoke to this kind of silo as well, coining the term “table engineers” to describe engineers who just sat around a table to solve problems—no interaction with the floor. These kinds of social barriers dwarf the technical challenges to effectively applying PDCA. 

At the executive level, strategy deployment often only feeds forward and then typically only to middle managers. In this case, the silos are vertical as well as horizontal. Eli Goldratt likened this approach to a game of chess, where the players were in a different room from the chessboard and can’t see their opponents’ moves. Check and adjust steps are not even possible. And the doers—employees who must implement improvements—are frequently not even aware of the big picture. Small wonder that the deployment aspect of strategy deployment is frequently lackluster. 

In fact, without acknowledging traditional organizational boundaries and applying intentional feedback loops, PDCA can be short-circuited between any two disciplines, yielding only the appearance of science. The problem to solve is not technical.

As Steve Covey noted, “A cardinal principle of total quality escapes too many managers: You cannot continuously improve interdependent systems and processes until you progressively perfect interdependent, interpersonal relationships.”

Where are your PDCA boundaries? Are they barriers or intersections? How are the interpersonal relationships?  Do pecking orders short-circuit PDCA? What systems do you employ to foster the free flow of information? Please share a thought.


About The Author

Bruce Hamilton’s picture

Bruce Hamilton

Bruce Hamilton, president of the Greater Boston Manufacturing Partnership (GBMP), brings hands-on experience as a manager, teacher, and change agent. Prior to GBMP, Hamilton led efforts to transform United Electric Controls Co.’s production from a traditional batch factory to a single-piece-flow environment that has become an international showcase. Hamilton has spoken internationally on lean manufacturing, employee involvement, continuous improvement, and implementing change. Also, he has contributed to numerous texts ranging from visual control to variety reduction. Hamilton’s blog, Old Lean Dude, is an ongoing reflection on lean philosophy and practices, with an emphasis on keeping good jobs close to home.


When PDCA Meets Silos

Agree with all the points and quotes. Valuable. However, there is a real reason why Dr Deming changed PDCA (Please don't change anything in some vernacular) to PDSA. Ford Motor Coy found that people were ''checking' quality with the go-no gages and that was fine on the lines but in essence inn using the Shewhart/Deming Control Charts, Ford queried Deming to request could they change Check to Study. This is what I was told by Ford and in either ex-President Caldwell or Petterson's books. Pyzdek explains it well too in Six Sigma Handbook. Dr Deming as I was told and paraphrased "PDCA was attributed to Dr Shewhart, it is his, not mine, yes PDSA reflects the Study of the process behavior / control chart to learn what the process is doing and to do nothing or take action on the process as Dr Shewhart and I said and trained you in his CC's, to assure stability before capability'.

I have a copy of the CWQC For Automotive Suppliers report written by LP Sullivan Ford MC Dearborn MI June 1985 and in Stage 3 QA Involving all departments pp48-49 "In many U.S. companies there is a significant inhibition to the more successful use of the quality team concept: strong vertical departments with separate performance objectives. When Dr Ishikawa was here in May 1983 he pointed out how U.S. companies are typically very strong vertically and somewhat weak horizontally; this characteristic effectively prevents the natural development of CWQC. He likened it to weaving cloth and why U.S. management does not understand this! The essence of Japanese style CWQC is to deploy the 'Voice of the Customer' horizontally through e company ; not vertically". My dear departed friend Dr Howard B Aaron Q.E.D. West Bloomfield Mi presented me this HB when in Sydney for the BHP QFD/Taguchi sessions for our largest steel manufacturer BHP Rod and Bar Division Newcastle NSW Australia.