5 Whys Analysis - Root cause analysis Tool

What is 5 Why? || When to use 5 Why? || How to use 5 Why? - Step by step instructions || 5 why root cause analysis Question || 5 why Process - Step by step instruction || 5 Why Analysis || 5 Why Filter Table

What is 5 Why?

" The 5 Why analysis is the initial tool used to determine the root cause of any problem. In 5 Whys analysis, we follow to solve any problem by repeatedly asking the question 'Why' 5 times. You may think Why 5 times? actually five times asking why is a good rule of thumb."

Remember that, 5 Why's is a root cause analysis tool, not a problem solving methodology. The 5 Whys' objective is to provide simple, but effective problem solving approach that will outcome in identifying the true root cause and suitable corrective actions for major quality problems. By the simply asking the question "why" you can bifurcate the symptoms from the cause of a problem to track significant symptoms of problems inline until you get real root cause of problem, because the "5 whys" is a simple tool that can help analyst to identify the root cause of problem.

When to use 5 Why?

Remember that, you don't want to list so many different reasons; you want to go deep on single reason. if you do the same process over and over, and expect to get different results, it might be time to try another approach. The technique provides a structural framework for team can conduct procedure to handle a more complex problem.

The technique offers some benefits are:

The 5 Why method assist to decide the cause effect relationship in failure occurrence and this is very simple way to try solving a stated problem without a statistical, mathematical, stressful investigation requiring many resources. And this is advantage of this technique. We are talking here about benefit so i would like to conclude here as: The 5 Why is beneficial because its (1) Simplicity (2) Effectiveness (3) Flexibility (4) Engagement (5) Inexpensive (6) Comprehensiveness.

How to use 5 Why? - Step by step instructions

As same as other tools and techniques, 5 Why also need to proper planning and preparation by effective team efforts. You have to focus on the problem to identify root cause for perfect corrective actions. The results of a 5 why's analysis is one or several root causes that ultimately identify the reason why a problem was originated. See the picture below, little effort for better understanding:

5 Why Analysis format, 5 Why Analysis template, 5 Why Analysis example, 5 Why Analysis pdf, 5 Why Analysis ppt, 5 Why Analysis  xls

The 5 why technique use a why table to sequential index the questions and their respective answers. The below table is an example of "5 why" delivered on appropriate issues. How each answer becomes the questions on next stage and each why question uses the previous answer establish clear link between them. Just simple questions and respective answer provides clues to understand, how particular problem occurred and what really needs to positive corrective actions for appropriate issues. So, lets the how we can track failure path by "5 Why" technique from the occurred.

5 why root cause analysis Question: Table

Why Question 3W 2H Answer (What, When, Where, How & How much) Evidence Solution
Why[ 1 ] Machine not starting? Because machine electrical input panel circuit not working. No power indicates machine's control panel --
Why[ 2 ] Electrical input panel circuit not working? Because circuit wiring shorted. Burning signs are found on circuit and connected wires. Remove burned wire and parts from circuit.
Why[ 3 ] circuit and wiring ignite? Because during the installation, wiring is not properly installed and due to wiring short, circuit parts are also burned. Wiring diagram not matched with installed wiring on circuit. Identify which part of circuit and wire will needs to install as right way.
Why[ 4 ] Wiring is not properly installed? On after verification with standard installation guide for input panel, wiring found randomly installed. Mismatch of physical wiring on circuit with standard installation guide as well wiring diagram. Re-install all wiring & circuit parts as per standard installation guide.
Why[ 5 ] Electrical engineer had mistaken during installation of wiring? Because he ignored to read and follow standard installation guide and followed old work instruction for installation of input panel. Old work instruction and standard installation guide for input panel is mismatched. Update all work instruction on periodic or as on new purchasing, new technology or any other update for instruction of machinery.

Here as above table is just an example to describe how the "5 why" technique perform in real case, it can possible you can ask more "Why" questions go into deep to identify root cause of problem. Actually "5 why" is standard rule of thumb.

5 why Process - Step by step instruction

When I was jointed industrial works, I listen the sentence "Well defined problem is a half resolved problem", hence, it is necessary that try to make you describe state the problem as clearly as possible. State the problem you have identified as a strategic problem to work on. How? here it is answer:
  • Write down the specific problem. Description of written the problem will assist you to structure the problem's solution.
  • it will help a team to focus on the same issue.
  • Try to describe current condition of processes, issues and merge possible related situation in statement.
  • Verify and use data information if customer dissatisfaction above unacceptable level.
Identify peoples knowledgeable about the area of non-conformance recorded, for build the team to do involve as many personnel as possible. Establish the problem statement with highlight the issues to decide whether or not additional individuals are needed to resolve the problem.
On presentation board or on paper, write down a full description of what details collected from non-compliance area. Prepare document the problem and describe it as completely as possible. refine details by discussion with team member to identify possible cause.
▽ How to conduct 5 Why Process? - Start asking questions "why-why" related to the problem:
  1. 1st Why: The first "why" question gives you plainly explanation the reason in short sentence. You have to use the first answer as the foundation of next question, but don't judge it instead of try to understand connection between processes and problem. May be person who is related with area where problem is occurred will gives you many reasons for particular problem, try to filter all those answers by brainstorming at on the stage first "why".
  2. 2nd Why: As on second stage of "5 Why", you have to go in deep to support the first statement on initial questioner stage's explanation. Try to go in to deep on technical details and verify which symptoms could raise as existing problem, you have to be clear on "know" and "unknown" to target root causes.
  3. 3rd Why: Do not come on conclusions yet, keep continue regular thought process to follow answer for understand. You have to concentrate on the area where the problem could have been first originated. On the stage of third of 5 Whys' will take you to a deeper comprehension of the problem. You can visualize the regular process map, product cycle and related processes to listing down the most likely sources for the problem to occur. This whole process is part of investigation, hence you have to interact with peoples and go to the processes to see things you could have missed at first.
  4. 4th Why: Clear your mind from preconceived notions and start the fourth stage with candid approach. You may have more different avenues to explore now, look for systemic causes of the problem and discuss these and settle on the most likely systematic cause. You can use problem solving tool like cause and effect analysis to explore all the included resources and processes like materials, machines, method, etc.
  5. 5th Why: Now you are on final stage of "5 Why", it is likely that you have get systemic cause hence the problems in the process can be traced on this stage, even related & hidden issues can be show up that is supporting to cause. When you address a systemic cause, do it across the entire process and detect locations that may be under the same situation even if there are no reported problems yet. Once the most probable root cause of the problem identified and confirmed, next step is should establish proper planning for corrective actions to eliminate the root cause from the system.

5 Why Analysis

5 why analysis form,5 why analysis worksheet, 5 why analysis case study,5 why analysis example, 5 why analysis excel, 5 why analysis pdf

Initially, you have to confirm that all those potential root causes are under your control by determine and apply some validations to your identified root causes. Ask the questions for every identified answers to identify all the levels of the 5 why as below:

5 Why Filter: Table

▽ Identify Problem:
  • Clealy State the problem
  • Write it down on flip chart
  • If there are multiple problems, write each of them down, and address separately, but choose the most critical
▽ Problem Clarified ( Basic Cause / Effect investigation)
▽ Area of cause located ( Where in the process is the problem occuring? )
  • Gather a diverse team
  • Gather infomration
  • Review the process itself and all related documentation
  • Educate yourself and the team
▽ Point of cause ( to go in the process to see the problem)
▽ First Why
  • Determine the first why?
  • Discuss and review with the team
  • Ask if you are looking at the problem from all aspects
  • Avoid Assumptions
▽ Second Why
▽ Third Why to Continue why? until root cause
  • Repeat the process for the remaining whys?
  • Keep probing until you come to an answer that you can control
▽ Root cause
▽ Corrective actions
  • Agree to root casue
  • Define the short term and long tem corrective actions
  • Investigate the systemic issue

The 5 Why methodology is related to the fishbone diagram and can be used to finish the analysis required to complete a cause and effect analysis process.


5 Why Analysis is structural process where you can organize the collected information in proper way and define it in an understandable manner. When the mentioned details cannot give a proper answer required for identify root cause, you have to keep continue for further investigation for identification of meaningful reasons and this is the advantage of "5 Why" analysis process. Remember that, the "5 Why" is not problem solving technique but more of a tool to aid to identify root cause of the defined problem. it will not the resolution of the problem itself, or standalone for elimination of problem, but this tool will more effectively assist in problem solving techniques.

First Published On Date: Monday, September 04, 2017 10:00 AM

Author: ARUN RAVAL | Business & Systems Analyst