5 Whys

The 5 Whys is a simple root cause analysis technique that helps you dig deeper into problems by repeatedly asking one fundamental question: “Why?” Think of it as peeling an onion. Each “why” question removes another layer until you reach the core of the problem.

The technique was developed by Sakichi Toyoda, founder of Toyota Industries, in the 1930s and became a cornerstone of the Toyota Production System. Toyota still uses it today, proving that sometimes the simplest tools are the most enduring. The technique gained wider recognition in the 1970s and has since been adopted across industries.

“5 Whys” gets its name from the general rule of thumb that it takes about five iterations of asking “Why?” to move past surface-level symptoms and uncover the underlying issue. However, you might need fewer questions for simple problems or more for complex ones. The number five isn’t a strict requirement but rather a helpful guide.

Start by stating your problem as specifically as possible. Be specific about what happened, when, and where. Instead of saying “Things aren’t working well at work,” try “We missed project deadline in the previous week by three days”.

Ask why this problem occurs and write down your answer. Focus on the immediate cause and strive to base your response on facts and observations rather than assumptions. For the missed deadline example, you might ask: “Why was the project deadline missed?” The answer might be: “Because the final report wasn’t completed on time”.

Take your answer from step 2 and ask “why” again (e.g. “Why wasn’t the final report completed on time?” Perhaps: “Because we didn’t receive the necessary data from the client until the last minute.”). Continue this process, with each answer forming the basis of the next question. Keep going until you arrive at something actionable or until asking “Why?” no longer produces a meaningful answer. Don’t worry about reaching exactly five levels. Some problems may need three whys, others might need seven or more.

Ask yourself: “If we address this root cause, will it prevent this problem from happening again?” If the answer is yes, you’ve likely found your target. You can also work backwards through your chain of reasoning using “therefore” statements to ensure your cause-and-effect relationships make sense (e.g. ”… therefore the final report wasn’t completed on time, therefore the project deadline was missed”).

Effective 5 Whys analysis typically points toward a broken process, missing system, or changeable behavior rather than vague answers like “not enough time” or “lack of resources”. If your final answer points to something you can actually modify or implement, you’re likely on the right track. You can also use the identified root cause to create action plans that prevent the problem from recurring.

• Stay factual and specific. Ground each answer in observable evidence rather than assumptions or emotions. If you don’t know the answer to a “why” question, that’s valuable information. It tells you where to investigate further.
• Avoid blame and focus on systems. The 5 Whys works best when you look for process breakdowns rather than pointing fingers at people. Instead of “because Sarah forgot,” ask “why was there no backup system when Sarah was unavailable?”
• Don’t feel constrained by the number five. Sometimes three “Whys” will get you to the root cause; other times you might need seven or eight. The number is less important than reaching a genuine root cause.
• Consider multiple pathways. Complex problems often have multiple contributing factors. If you discover several potential answers to a “Why?” question, explore each pathway separately.
• Consider multiple perspectives. If applying this to relationships or team situations, involve others in the process to get different viewpoints. What seems obvious to you might not be the full picture.

Let’s say you’re consistently running late for important meetings:

Problem: I’m always late for morning meetings.

Why #1: Why am I always late? Because I leave home later than planned.

Why #2: Why do I leave home later than planned? Because I spend too much time getting ready in the morning.

Why #3: Why do I spend too much time getting ready? Because I can’t find my clothes and have to search through my closet.

Why #4: Why can’t I find my clothes? Because my closet is disorganized and everything is mixed together.

Why #5: Why is my closet disorganized? Because I never established a system for organizing my clothes.

The root cause isn’t running late. It’s the lack of an organizational system. The solution might involve spending time organizing your closet and establishing evening routines to prepare for the next day.