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--- articles:whac-a-mole [2019/05/27 19:02] – rrandall
+++ articles:whac-a-mole [2019/05/29 10:21] – [Corrective Action... and "Whac-A-Mole"] rrandall
@@ Line 5: / Line 5: @@
 While "Corrective Action" is an essential component for any quality management system, surprisingly few quality professionals have a good understanding of it. This is most often because so many quality professionals lack a basic understanding of "Common Cause" vs "Special Cause" variation in a process.
+These concepts were first described by [[https://en.wikipedia.org/wiki/Walter_A._Shewhart|Walter A. Shewhart]] in his 1931 book, "//Economic control of quality of manufactured produc//t". And promoted by the [[https://en.wikipedia.org/wiki/Western_Electric|Western Electric Company]] in its 1956 book, "//Introduction to Statistical Quality Control handbook//" (1 ed.). Later, these concepts were popularized by [[https://en.wikipedia.org/wiki/W._Edwards_Deming|W. Edwards Deming]] in his 1982 book, "//Out of the Crisis: Quality, Productivity and Competitive Position//". Unfortunately, there are still many quality professionals who remain oblivious to these concepts!
 ===== Common Cause vs Special Cause Variation =====
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 Unlike the silverware issue, this is an unusual / abnormal, situation that has not previously occurred. Therefore, this would be a “special cause” variation in their process __with an assignable root cause__). Special causes produce systematic effects/errors in a process.
+The [[https://support.minitab.com/en-us/minitab/18/help-and-how-to/quality-and-process-improvement/control-charts/supporting-topics/basics/using-control-charts-to-detect-variation-in-a-process/|Minitab® 18 Support web site]] offers the following table as "**Examples of common-cause and special-cause variation**".
+^  Process  ^  Common Cause of Variation  ^  Special Cause of Variation  ^
+| Baking a loaf of bread  | The oven's thermostat allows the temperature to drift up and down slightly.  | Changing the oven's temperature or opening the oven door during baking can cause the temperature to fluctuate needlessly.  |
+| Recording customer contact information  | An experienced operator makes an occasional error.  | An untrained operator new to the job makes numerous data-entry errors.  |
+| Injection molding of plastic toys  | Slight variations in the plastic from a supplier result in minor variations in product strength from batch to batch.  | Changing to a less reliable plastic supplier leads to an immediate shift in the strength and consistency of your final product.  |
+As shown in the above examples, a control chart isn't always needed to differentiate between a "Common Cause" and "Special Cause" variation. However, because far too many quality professionals fail to differentiate between "Common Cause" and "Special Cause" variations in a process, a very large number of nonconformities from "Common Cause" variations are incorrectly addressed through the corrective action process. This leads to a cycle resembling the 1976 arcade game, "Whac-A-Mole" (where moles pop up from their holes at random, and the player earns points by forcing them back into their hole through hitting them directly on the head with a mallet). In the end, nothing is accomplished... other than the player feeling a false sense of accomplishment reflected by their score. In this case, the quality team "feels" good (a false sense of accomplishment) about the apparent (short term) success of each corrective action.
-However, had there been an unusual condition leading to excessive debris on the bike train (e.g., such as high winds or a tornado through the area), then this would have been a "Special Cause" variation (i.e., an "unnatural pattern" in the process, which is unusual, not previously observed, non-quantifiable variation in the process __with an assignable root cause__). Special causes produce systematic effects/errors in a process.
-Because far too many quality professionals fail to differentiate between "Common Cause" and "Special Cause" variations in a process, a very large number of nonconformities from "Common Cause" variations are incorrectly addressed through the corrective action process. This leads to a cycle resembling the 1976 arcade game, "Whac-A-Mole" (where moles pop up from their holes at random, and the player earns points by forcing them back into their hole through hitting them directly on the head with a mallet). In the end, nothing is accomplished... but the player has a false sense of accomplishment reflected by their score. In this case, the quality team "feels" good (a false sense of accomplishment) about the apparent (short term) success of each corrective action.
-Only through first determining whether each nonconformity is a "Common Cause" or "Special Cause" variation, can "real" corrective action can be realized.
 ===== Reactive vs. Proactive Process Improvement =====
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 ==== Proactive Process Improvement ====
-Because "common cause" variations are inherent to the existing process, these variations can only be eliminated by significantly "modifying" or "re-designing" the existing process. The most effective process improvement activities are realized through applying the Lean Six Sigma concepts & methodologies.
+Because "common cause" variations are inherent to the existing process, these variations can only be reduced or eliminated by significantly "modifying" or "re-designing" the existing process. The most effective process improvement activities are realized through applying the Lean Six Sigma concepts & methodologies.
 As a process is being "modified" or "re-designed", one of the best tools to use is the [[https://asq.org/quality-resources/fmea|"Failure Mode and Effects Analysis" (FMEA)]]... or FMECA ("Failure Mode, Effects and Criticality Analysis").