When you think about the Toyota brand, what comes to mind? For a lot of people, reliability is what they think of. There are many Toyotas running today that are 10+ years old and still going strong. What’s interesting is that this was not how people always viewed Toyota. It used to be that Toyotas were seen as a low end, low quality brand that was anything but reliable.

Clearly something changed for such a turnaround to take place, and that’s what I want to explore in this blog post because I think the strategy they used can apply to math education as well. In 1950s, as Toyota changed its production system, they implemented a technique called 5 Whys. This technique was ludicrously simple yet startlingly powerful.

The basic premise was that when an undesired result happened, you would ask why it happened. Then when you got that answer, you would ask why that happened. This process would happen a total of five times and get them much closer to the root cause of an issue. Here’s an example from Wikipedia:

The Problem: The vehicle will not start.
Why #1: The battery is dead.
Why #2: The alternator is not functioning.
Why #3: The alternator belt has broken.
Why #4: The alternator belt was well beyond its useful service life and not replaced.
Why #5: The vehicle was not maintained according to the recommended service schedule.

What it’s important to realize is that if you just looked at the initial problem (the battery was dead) you would probably be concerned about the quality of the batteries you were using. The reality though was that the battery wasn’t the problem at all. Nor was it the alternator or alternator belt. The problem was that the vehicle was not being maintained properly, but that wasn’t initially obvious. By the fifth time you asked why, it got much closer to the root cause.

Clearly not all problems have a single root cause and not all root causes can be found in five questions, but it’s an improvement over the status quo. The important part is that we often only ask “Why?” once or not at all. This leaves us with two troubling possibilities: we may have no idea what the problem’s real cause is or (perhaps worse) we think we know what the real cause is but haven’t dug deep enough to know for sure.

Application in Education
Consider its application in education:

The Problem: A student is failing her math class.
Teacher A: (Why #1) Why is the student failing her math class?
Teacher B: Because she didn’t pass the test.

This is usually as far as it gets when parents talk to teachers. Unfortunately, at this point Teacher A can say why the student is failing yet doesn’t have anything actionable to use. Let’s continue with the whys.

Teacher A: (Why #2) Why didn’t she pass the test?
Teacher B: Because she chose many common wrong answers.
Teacher A: (Why #3) Why did she choose many common wrong answers?
Teacher B: Because she’s trying to repeat a procedure without understanding it.

Now we’ve asked why a total of three times. We’re definitely closer to having something actionable than we were when we only asked why once. We could stop here and help the student better understand the procedures and call it a day. That would seem reasonable. However, let’s ask why two more times and see where it takes us.

Teacher A: (Why #4) Why is she only trying to repeat a procedure without understanding it?
Teacher B: Because she doesn’t have conceptual understanding.
Teacher A: (Why #5) Why doesn’t she have conceptual understanding?
Teacher B: Because we didn’t have enough time so we skipped that section.

Ah, so asking more whys reveals a deeper issue! Perhaps in this case, the issue is not only the student. While this is obviously a contrived scenario, I’m sure you can imagine this playing out in your past experiences. I bet you also realize that we could ask even more whys, dig deeper, and explore why teachers don’t have enough time!

I hope this has been an interesting exploration for you. I imagine that this technique would be especially powerful in situations where groups of educators brainstormed for solutions to complex problems. For example, many schools have teams of teachers that come together to discuss struggling students. This might be helpful there. Maybe this could also be helpful when teachers are trying to figure out next steps after seeing disappointing assessment results.

What do you think? Where else might this be useful for educators to use? Maybe you’ve used this and can share your experiences? Please let me know in the comments.


  1. I’m glad you wrote this Robert. This strategy is simple, yet requires discipline to develop as a habit of mind. There are two times I have undergone this process in my 15 years on the teaching side of education, both were in the last four. As a coach with the Hollyhock Fellowship ’16-’17, we used the 5 Whys strategy to climb the ladder of inference (inspired by Elena Aguilar’s book, The Art of Coaching). Currently, as a partnerships manager with Teaching Lab ’19-’20, we use 5 Whys with partners to map out the system of related causes for a problem area (inspired by New York City DOE’s Improvement Science efforts).

    This strategy helps to avoid jumping to quick solutions that don’t address root causes as you illustrate nicely in your examples above. Thanks, and your talk at GSDMC20 was superb!

    • Thanks Evan. I’ve found that it’s been useful in helping me unpack some complex issues that and learn history I was unaware of. For example, I wondered a question of “Why are there not more educators of colors presenting at teacher conferences?” The answer was because many did not apply to speak. “Why did many educators of color not apply to speak?” Then this sent me in all directions. I learned more about the cycle created by a lack of representation. I learned more about the history of racism that prevented people of color from living in certain areas and getting jobs in education. When I asked why that had happen, it kept branching out and going to important areas I knew little about.

      So sometimes we get more questions than answers, but at least we’re asking the right questions.

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