The title of Art Smalley’s new book, Four Types of Problems, is misleading. It doesn’t actually address four types of problems. Rather, it covers four types of problem solving. In that regards, it’s an excellent reference book that belongs on every bookshelf.  

Smalley starts with the hoariest example of root cause problem solving: the machine tool that stops working because of insufficient lubrication. This is the classic example that probably every consultant has used to demonstrate the 5-Why approach to finding root cause. Smalley points out, however, that in focusing on the 5-Whys in this story, we’ve missed the bigger picture—that there are actually four ways to address this problem, and we need to be skilled in of all of them. (And, in fact, Toyota has used all four types over the years to deal with this issue.) 

Smalley helpfully categorizes these four approaches using the machine tool example:

  • Type 1: Troubleshooting.Quick response that provides immediate relief without getting at the root cause. In the case of the machine tool, this was cleaning the metal chips off the tool during the shift so that it wouldn’t seize up. Of course, this led to significant down time. 

  • Type 2: Gap from standard.Identifying the root causes of a problem that prevent something from operating as it should. The 5-Why inquiry that identified the lack of a strainer, and kept production on target, is emblematic of this type of problem solving. 

  • Type 3: Target condition.Setting a higher standard than is currently used and reaching it through kaizen. This type of problem solving led Toyota to figure out how to reduce the need for cleaning out the metal chips so that they could run the tool with higher uptime and shorter lead time in the service of better meeting customer demand. 

  • Type 4: Open-ended.Innovation that seeks to fundamentally change how something operates. Toyota added sensor technology, industrial washers, and larger combined systems to better manage the cutting chip waste. 

So again, not four different types of problems, but rather, four different ways to deal with the one problem of cutting chip waste buildup. 

After a chapter-long digression on the history of problem solving approaches, Smalley takes a deep dive into each of the four types of problem solving. He discusses the conditions that call for each approach, identifies key points of each one, and calls out their strengths and weaknesses. There are valuable insights in this section that I’ve often overlooked. For example, in Type 1 problem solving, Smalley cautions that “people naively assume that documentation and training are the best or only way to make countermeasures stick. That view is incomplete and should be challenged.” Similarly, “a weakness of this method [Type 2 problem solving] is that it can lead to an attitude of acceptance of the status quo, which can lead to a general lack of inventiveness.” I know that I’ve fallen prey to this tendency in my own consulting.

His most compelling warning—which all people pursuing continuous improvement should remember—is this:

Some organizations will try to jump from Type 1 troubleshooting to Type 3 level of improvement activities to save time. This strategy will rarely be successful. Even when it is, the success is essentially a matter of luck. The necessity of tackling existing gap-from-standard problem cannot be wished away or ignored in favor of a Type 3 approach. Gap-from-standard problems are rampant in most organizations, and they require the discipline of definition and root-cause analysis to solve and ensure stable operations. 

He points out that Toyota’s remarkable success in Type 3 (improve the target condition) problem solving is built upon its focus on Type 1 (troubleshooting) problem solving in the 1950s and ‘60s, and its subsequent attention to Type 2 (gap from standard) problem solving skills. 

The section on Type 4 problem solving is a foray into the world of innovation and the various approaches to it: lean startup, design thinking, set-based product development, TRIZ, etc. all get their turns on stage here. “Innovation” seems to be the business buzzword of recent years, which makes Smalley’s admonition against “succumbing to the allure of breakthrough innovations to the neglect of the first three types of problem-solving approaches” all the more important. 

If you’re familiar with the different ways of approaching problems, Four Types of Problems is a useful reference book. If you’re introducing your team to the concept of a methodical, structured approach to problem solving, this is an invaluable primer. You won’t need to look at it all the time, but you’ll be glad to have easy access to the information. 

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