Highly Compatible

Enhance your improvement efforts by coupling ISO 9001:2015 with the theory of constraints

by Paul Palmes

According to ISO 9000:2015, “quality” is defined as the “degree to which a set of inherent characteristics of an object fulfils requirements.”1 The same document further defines “characteristic” as a “distinguishing feature.”2 A great deal of what follows relative to our appreciation of quality—good or bad—therefore relies on customers’ real-world understanding of those characteristics and whether the product or service meets customers’ requirements.

Of course, what customers imagine as a product or service requirement is actually a complex set of expectations. The customer may expect more or less of one or more distinguishing features, and the organization may expect the product to be appreciated for characteristics whose importance can, and often does, vary among users.

An example

To illustrate, imagine that Organization A offers a product priced well below the market rate with a 90-day limited warranty. Organization B offers the same product at a significantly higher price, but boasts the strongest warranty on the market.

Both products share the same shortcomings—Organization B just charges for turnaround and replacement. Both products are of equal quality in relation to one or more characteristics that are rarely the subject of complaint, such as paint finish. Regardless, those paint characteristics have been defined, if only because the lack of complaints informs both organizations that the paint finish is uniformly acceptable in the marketplace. The real issue is whether the organizations are learning anything as they blunder through the one characteristic they both offer to their customers: disappointment, as they both face high returns.

ISO 9001:2015 is a management system standard that requires careful planning and execution, and the opportunity for the organization to learn and improve by analyzing its performance. In the example, the source of disappointment can be discovered through review of initial planning and performance analysis, and remedies determined through further planning and redesign.

Throughout all this study, the processes that rely on one another to produce the final product also are examined to determine possible weaknesses and opportunities for improvement. Product characteristics are examined, starting with the key complaint characteristic driving high returns. That characteristic remains at the center of everyone’s attention as processes and practices are examined to determine the internal characteristics that enabled or created the problem characteristic and a workable solution is crafted.

And so it goes. In time, performance analysis indicates that the return rate has dropped significantly for one of the organizations in this example. From all appearances, there is a new appreciation for the product and the organization that finally fixed the problem. That is, until product longevity—previously a rarity—emerges as the prime complaint for premature wear of paint finish. Apparently, getting out of trouble isn’t necessarily the same as staying out of trouble.

The theory of constraints3, 4 (TOC) is constantly at work as one constraint is overcome and replaced by another. TOC and ISO 9001:2015 are highly compatible and often perform the same functions as problems are identified and managed for improvement. Substitute “problem” or “defect” with “bottleneck,” and the process of remediation is essentially the same.

Better together

The marriage of a standard and the practical understandings of a sound business approach carry a host of opportunities for organizations implementing ISO 9001:2015 for the first time or for those in search of improving a certified quality management system. TOC’s central principles of convergence, consistency and respect are an excellent starting point for any organization—certified or not—to gain perspective and insight into the nature of work and working together in a complex system.

Convergence, or the understanding that adjusting one process will affect all other processes, is fundamental to ISO 9001:2015, clause 4.4.1.b. Ultimately, convergence was the foundation of the paint finish problem because adjustments for product longevity failed to factor in additional surface wear and perhaps weatherization testing. Organizations that use convergence to their advantage are less inclined to discount the importance of ISO 9001:2015, clause 4.4.1.

Consistency’s message is that a flawed assumption is at the root of whatever’s not meeting expectations. Coupled with the principle of respect for everyone in the system, TOC builds a culture of acceptance and the understanding that mistakes are to be expected during the improvement process and change in general. The requirements of ISO 9001:2015, Clause 7.2—Competence and Clause 7.3—Awareness are humanized in the backdrop of these principles.

It’s no surprise that one system is compatible with another, but might be surprising that some combinations are more supportive than others. The study, adoption and coupling of ISO 9001:2015 and TOC is not only supportive, but also additive.


  1. The International Organization for Standardization (ISO), ISO 9000:2015—Quality management systems—Fundamentals and vocabulary, clause 3.6.2.
  2. Ibid, clause 10.3.1.
  3. James Wilkinson, “Theory of Constraints Definition,” The Strategic CFO, July 24, 2013, https://strategiccfo.com/theory-of-constraints.
  4. Theory of Constraints Institute, “The Goal Summary & Book Review,” www.tocinstitute.org/the-goal-summary.html.

Paul Palmes is principal consultant with Business Systems Architects Inc. in Fargo, ND, and Prescott, WI. He is chair of the U.S. Technical Advisory Group to the International Organization for Standardization Technical Committee (ISO/TC) 176, and chair of ISO/TC 176, subcommittee 1, responsible for ISO 9000:2015. He is the coauthor of Business Sustainability: Going Beyond ISO 9004 (ASQ Quality Press, 2018) and ISO 9001:2015: Understand, Implement, Succeed! (Prentice Hall, 2015), and author of Process Driven Comprehensive Auditing, second edition (ASQ Quality Press, 2009) and The Magic of Self-Directed Work Teams (ASQ Quality Press, 2006).

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