Saying “no” to waste – Step 2: Uproot root causes

In the last post we talked about identifying wastes. Now we are going to get to the bottom to find the root of the problem. When you go to the deepest cause of problems, you deplete the chances to repeat them.


(Taken from

Determining root causes:

In other posts I mentioned the difficulties that many companies experiment finding the real cause of their problems although this is a key step in the process to solve wastes; wrong root cause, wrong solution, that´s it.

My favourite technique to find root causes is a 5 Why Analysis. It is simple, quick, and very practical. The idea is that by asking “Why?” up to five times –or more, this is not limitative-, you will reach an answer that is readily apparent the root cause (Goldsby & Martichenko, 2005)

Another good way to reach the bottom of problems is cause-and-effect diagrams, known as fishbone or Ishikawa diagrams as well. I would say that cause-and-effect diagram is a good trigger to unchain a deeper analysis; because despite attack several potential sources, like process, technology, equipment, material and people, it´s not determinant to confirm a root cause. The main purpose of these diagrams is to generate discussion that can close in on the root cause or causes of a focal problem. (Goldsby & Martichenko, 2005)

I like to combine the format of 5 Why´s with the approach of a fishbone diagram. The method is simple, after defining the problem the first whys are focussed to resolve the different potential sources recommended in an Ishikawa. I illustrate it with the figure below. If you want to get the format, you can download it here. 5W alanrodesp format

5W example

One Why could derive two or more Whys in next level, that´s the reason I use two cells in each level though use it is not mandatory. The apparent root causes could be more than one, the idea of this format is to attack all the potential causes of issues, this way you are reducing the possibility of relapse. You always can adapt the format according to your needs.

Setting an action plan

Each root cause needs an action; not a simple action, it has to be a robust action plan that assures the reduction or elimination of occurrences.

Action Plan

At this point you must have your process perfectly measured to validate each root cause found in your analysis and setting your goals. We have talked about measuring previously. Then, approach the WH questions is a basic.

What? Your solution has to cover each failure mode of your process, you can use poke yokes, sensors, check lists, scans, etc. Have special attention in the effect of each action on the root cause.

When? Don´t leave open dates, it is an invitation to delay everything. Usually an employee says “let me check first, then put a date”, no! Estimate dates, it´s easy to imagine “Contact supplier, get quotes, set PO, receive material, installation, training… 3 weeks”. Maybe you will have to make revisions to dates but you are committing your team. Remember that this works as a clock, if seconds hand is stopped, it stops the minute and hour hands too

Who? You have to be sure that correct people are involved and aware of their responsibilities. Sometimes the leader creates the action plan in its desk and there is not a launch meeting or something similar to share and discuss the plan. Putting names in action plans is not magic, call a meeting to share out the tasks

How? Consider tools in this question, confirm that you have all set to start and comply on time. You can download a quick PDCA (Plan, Do, Check, Act) format here  to support the task. Quick PDCA alanrodesp format

In two weeks I will publish the third step of this series. I wish you good luck with the first two steps.

Thanks for your likes, shares and comments. Until next one!

Alan Rodríguez



Goldsby, T., & Martichenko, R. (2005). Lean Six Sigma Logistics. Strategic development to operational success. (J. R. Publishing, Ed.) Florida, US: J. Ross Publishing.

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