The Brilliance Behind the 5 Why's: The Leanest of All Lean Tools

I have some terrible news. I hate to have the one to inform you of this. But…if you or your people are no good at solving problems, you can’t do Lean. Don’t waste your valuable time running out to the production floor to do 5S, kanbans, or even OEE. You’ll get your hopes up high just to watch them come crashing down after a couple of weeks when you start to see all the great work you did just isn’t sustaining. It will break your heart after investing so much political and emotional capital and getting everyone else so excited about Lean, just to end up feeling like Lean doesn’t work for us – just another flavor of the month.

But don’t give up hope. What I’m about to say in this blog post will change the trajectory of your Lean journey and put your initiative on the path to lifelong growth and sustainability (just pretend with me like that statement is not an oxymoron).

What is the 5 Why’s?

I assume you’ve probably heard of the 5 Why’s but I’ll give you the quick and dirty. It’s essentially a little technique that helps you identify the root cause of an issue simply by asking Why 5 times. The 5th Why (sometimes more or less) should get you pretty close to the root cause.

For example, a 5 Why’s Analysis might look something like this:

Problem: The conveyor system keeps failing

1st Why: The motor is running high amperage and shutting down

2nd Why: The motor is failing

3rd Why: The motor and gearbox have been lubricated very infrequently since they were installed

4th Why: No one is checking the lubrication record to see when the next lubrication is needed and lubricating

5th Why: There is no scheduled preventative maintenance in place for this motor

Logically, one would conclude to implement a PM, or even better, an Operator PM or self-lubrication system to lubricate the motor on a regular basis to avoid future failures.

How Are You Supposed to Do The 5 Why’s?

Although many people just complete the 5 Why’s as a conference room activity, which is a huge step forward from doing no root cause analysis at all. Ideally, the 5 Why’s would be done along with validating the “truth” in each of the assumptions made during analysis. The fact is that each of the Why’s listed above is a hypothesis that needs to be validated by testing the process to see if it actually changes the outcome, or even better, produces the desired outcome. If the 5 Why theory holds true, once you get to the 5th Why, then you have found the root cause.

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Why the 5 Why’s is so Powerful

There is no typo there. The 5 Why’s is immensely powerful. I’ll list 2 damn good reasons why but I’m sure you can come up with a half dozen more if you put your mind to it.

Reason #1: In identifying the root cause of one issue and fixing it permanently, you have also solved a whole boatload of other problems. So there’s a multiplier effect of getting this right. Take the example above regarding the PM for the conveyor motor. You can probably imagine that this conveyor failing is causing other reliability issues up and down the line due to the erk and jerk of frequent stopping and restarting. Also, I’d be willing to bet my allowance money that there are a bunch of other motors / gearboxes in your plant that also need to be set on a lubrication schedule.

Reason #2: Probably 99% of humans older than age 6 could effectively handle asking Why 5 times to get to the Root Cause. Okay maybe 99% is an overstatement but I’ll venture to say that all of your employees, managers, and colleagues can handle it just fine.

That’s another reason why I love Lean and Continuous Improvement. After spending too much of my life in undergrad for Industrial Engineering, half-killing myself pulling all-nighters to pass tests designed to demonstrate my inferiority and make me pay twice to retake each class, I get to the real world and learn that the best Industrial Engineering tools out there can be successfully executed by a six year-old.

Root cause analysis is at the heart of Dr Deming’s PDCA (Plan – Do – Check – Act) model of Continuous Improvement. The 5 Why’s is undoubtedly one of the most powerful Root Cause Analysis tools as it applies the logic behind what’s driving the problems we see everyday, regardless of complexity. So go forth and apply this wisdom to your stickiest of problems and at least (but not last) start to build the ever-so-needed problem solving capability. Couple this behavior with a good management system to get everyone using it regularly and you’ve got a recipe to build an unstoppable growth machine.