When an error repeats, the first explanation is usually the nearest one: someone was careless, or someone was slow. Fixing that explanation rarely stops the error. This Practice keeps asking why until the answer is a step in the process that can be changed. The fix goes there, and the error stops coming back.
A tool that supports it
Root Cause Diagnosis is a behavior, and more than one method can lead you to a cause. The one this Practice is built on is the “5 Whys,” a method from Toyota. It’s credited to the company’s founder, Sakichi Toyoda, and Taiichi Ohno later described it as the basis of how Toyota solves problems.
It works as a chain. You state the error and ask why it happened. Then you take the answer and ask why again. Each answer becomes the subject of the next question, and each one moves a step away from the person and closer to the process.
The five is a rule of thumb. Some chains end in three questions and some need six. You’ve reached the end when the answer is something you can change this week, like a form or a permission.
When to use it
Use it for a routine error that has happened more than once. The signal is a fix that sounds like “let’s all be more careful.”
It suits errors with one main cause, where the people who do the work can answer the questions. A problem with several causes at once needs a wider map than a single chain.
How to use it
- Write the error as a fact, with how often it happened.
- Ask why it happened, and write the answer down. Use what people saw, and leave guesses out.
- Ask why about that answer. Keep going, one question per answer.
- When an answer blames a person, ask what made the mistake easy to make. Getting past the person is the hard part.
- Stop at a cause you can change, and change it.
Example
A design agency sent six invoices to the wrong address last month. Finance raises it in the weekly team meeting.
The account manager asks the questions. Why did the invoices go to the wrong address? Finance copied it from the client record, and the record was old. Why was it old? When a client moves, they tell their salesperson by email, and the news stays in the email. Why doesn’t the salesperson update the record? Only finance can edit it. Why? That permission was set years ago, when the team was three people.
Finance opens the field to the sales team that afternoon. The next month, every invoice reaches the right address.
Phrases you can use
- “Before we fix it, why did it happen?”
- “And why was that?”
- “What made that mistake easy to make?”
- “Is that what we saw, or what we think?”
- “We can change that this week. Let’s stop there and fix it.”
- For a leader, when someone does it: “You kept asking until you found something we could change. Has the error come back?”
How to know it worked
The fix changes a step in the process, and nobody is asked to try harder. Over the next few weeks, the error doesn’t return. With time, people on the team ask “why?” a second time on their own before proposing a fix.
In a Skill Deck Track on Problem Solving, a person can choose this Practice, and the meetings they already have show when they use it.
skilldeck.ai
