Tool: 5 Whys

Usage: Defining a problem (determining the root cause) 

The Five Whys helps to identify the root cause of a problem and is a simple, yet powerful tool. The technique originated within Toyota while developing their manufacturing methodologies, and is a key component of their problem solving training.

Asking the question ‘why?’ repeatedly (five times is a rule of thumb) allows a team to peel back layers of a problem or issue, which can lead to the root cause. The reason for a problem may lead to further questions, and it may take fewer – or more – than five ‘whys’ to expose the root cause. Once the root cause has been identified, action can be taken to deal with the problem. This technique enables teams to target their improvement work on the actual cause of the issue, and avoid unintentionally focusing on the symptoms.

How to complete the five whys

  1. Write down the problem. Describing it as accurately as possible will help keep the team focused on the same issue.
  2. Ask why this happens (write it down).
  3. If this does not identify the root cause, ask why again (write it down).
  4. Repeat step 3 until the group agrees on the root cause.
  5. The group will know they have identified the root cause when asking ‘why’ does not provide any more useful information.


The patient was not aware of the PCEHR.
Why?       The patient did not receive a letter explaining the PCEHR.
Why?       The patient is not on the CHD register (and we targeted our letters to patients with CHD).
Why?       Conducting a search using the agreed terms for CHD did not identify this patient.
Why?       Some patients have not been correctly coded in the medical software.
Why?       Part-time staff have not received training on the agreed terms for CHD and how to code patients.
Action:     Ensure all team members are trained on the agreed terms for CHD used in the practice and how to code correctly in the clinical record.

Adding this patient to the CHD register would have solved the immediate problem, but would not ensure that it doesn’t happen again with other patients. By addressing the root cause of the problem and training part-time team members, the chance of this problem occurring again has reduced significantly


  • Focus on the process rather than the people (a culture of blame is not conducive to quality improvement).
  • Avoid making assumptions about a problem when working through the five whys.
  • Communicate the outcomes of the process to ensure that the root cause is understood by those involved and that the improvement effort is focused on the underlying cause, and not symptoms of the problem.