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The ‘5 Whys’ Technique In Lean Continuous Improvement Programmes

Updated: Nov 17, 2023

The ‘5 whys’ is a problem-solving technique to identify the root cause of an issue by repeatedly asking “why” in a structured manner. The goal is to dig deeper into the issue rather than just superficially addressing the problem.

Aligning with Lean thinking of eliminating waste and improving overall outcomes, the tool is particularly valuable in Lean Continuous Improvement. In this blog, we’ll unpack the ‘5 whys’, how the method works, and explore its real-world applications.

5 people holding up signs with why written on them

Understanding the ‘5 whys’

Identify the problem. Start by clearly defining the problem or issue you need to address. Keep it specific and measurable so you can track progress.

Ask the first “why”. Your first question should be: Why did the problem occur? Use observable facts or data – for example, if the problem is a fault in a product, you might ask, “Why did the defect occur?”

Ask “why” four more times. Continue asking “why” until you reach the root cause – and further questioning doesn’t yield anything useful. The key is to go beyond superficial answers.

For example…

  • First “why” – The defect occurred because a machine malfunctioned.

  • Second “why” – Why did the machine malfunction? Because it wasn’t properly maintained.

  • Third “why” – Why wasn’t it properly maintained? Because the maintenance schedule wasn’t followed.

  • Fourth “why” – Why wasn’t the maintenance schedule followed? Because the maintenance team is short-staffed.

  • Fifth “why” – Why is the maintenance team short-staffed? Because of budget constraints and hiring freezes.

By the fifth “why,” you should ideally have identified the root cause of the problem.

Implementing the technique in problem-solving

With the root cause identified, you can start developing and implementing solutions to address the underlying issue. In our example, you might find ways to secure an additional budget for hiring maintenance staff or optimise existing processes.

Monitor and evaluate

After implementing the solutions, it’s essential to monitor the situation and evaluate whether the problem has been effectively resolved. If not, you can repeat the 5 Whys process or consider other problem-solving techniques.

Lean case studies: real-world applications

person with laptop viewing a lean case study

In this case study, a medical manufacturing company successfully implemented Lean transformation in their business – resulting in a significant boost in sales. However, this meant they needed to expand their existing warehouse or required a new, larger one to store parts.

Their solution? After a root cause analysis of the problem, they created a “plan-for-every-part” database, which allowed them to integrate the pull system with the ERP system’s data. They convinced their suppliers to join their pull system so they could order parts based on real-time demand rather than forecasts.

Now, their inventory management is more efficient, and they don’t need a bigger warehouse. They also have better relationships with their suppliers and can accommodate changes in demand more easily. Overall, by getting to the root cause, they saved space and money while improving their operations – rather than superficially fixing the initial issue.

Here’s what we can learn…

1. Identify the root cause

The first step in preventing recurring issues is to identify the root cause with the ‘5 whys’. In this case, the company had tripled its performance with minimal growth in operating costs, just as intended. However, as overall sales continued to rise, the company found it needed to expand its on-site warehouse.

2. Objective

Constructing a new or larger warehouse would have been an expensive option. The company wanted to avoid this by speeding up the flow of parts through its current facility.

3. Solution

To achieve this, the supply chain team needed to extend the existing pull system to suppliers. They also had to merge individual inventory items into a single, streamlined pull system that would be simple to upkeep and oversee.

4. Continuous Improvement

By addressing the root cause and making necessary changes, the company was able to prevent similar issues from occurring in the future – highlighting the importance of a Continuous Improvement mindset.

All warehouse locations are checked every 30 days, identifying low-risk abnormalities to review weekly and immediately addressing high-risk abnormalities.

5. Documentation

Documenting the entire process, from issue identification to resolution, helps share knowledge within the team and serves as a reference for similar issues down the line.

Effectively transform your business with the ‘5 whys’

Systematic problem-solving techniques, like the ‘5 Whys’ technique, are vital to address root causes and prevent recurring issues. In Lean Continuous Improvement programs, the ‘5 Whys’ promotes a simple and adaptable method that encourages teams to address issues at the source rather than applying quick fixes.

By continuously seeking out and eliminating root causes, organisations can improve their processes, reduce waste, and enhance overall efficiency and quality.

To learn more about the ‘5 whys’ and Continuous Improvement, reach out to us at 0161 533 1617, email, or on our website.



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