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When confronted with a problem, have you ever stopped and asked “why” five times? If you do not ask the right question, you will not get the right answer. The Five Whys is a simple question-asking technique that explores the cause-and-effect relationships underlying problems.
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e Five Whys Technique
Olivier Serrat
Asian Development Bank
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e Five Whys Technique
{Excerpt} When confronted with a problem, have you ever stopped and asked “why” ve times? If you do not
ask the right question, you will not get the right answer. e Five Whys is a simple question asking technique
that explores the cause-and-eect relationships underlying problems.
For every eect there is a cause. But the results chain between the two is fairly long and becomes ner as one
moves from inputs to activities, outputs, outcome, and impact. In results-based management, the degree of
control one enjoys decreases higher up the chain and the challenge of monitoring and evaluating
correspondingly increases. In due course, when a problem appears, the temptation is strong to blame others or
external events. Yet, the root cause of problems oen lies closer to home.
Asian Development Bank, ADB, poverty, economic growth, sustainability, development
Suggested Citation
Serrat, O. (2010). e ve ways technique. Washington, DC: Asian Development Bank.
Required Publisher's Statement
ADB encourages printing or copying information exclusively for personal and noncommercial use with
proper acknowledgment of ADB.
is article is available at DigitalCommons@ILR: hp://
February 2009 | 30
When confronted
with a problem, have
you ever stopped
and asked “why”
ve times? If you
do not ask the right
question, you will not
get the right answer.
The Five Whys is
a simple question-
asking technique
that explores the
underlying problems.
The Five Whys
by Olivier Serrat
For every effect there is a cause. But the results chain be-
tween the two is fairly long and becomes ner as one moves
from inputs to activities, outputs, outcome, and impact.1 In
results-based management,2 the degree of control one enjoys
decreases higher up the chain and the challenge of monitor-
ing and evaluating correspondingly increases.
In due course, when a problem appears, the temptation is
strong to blame others or external events. Yet, the root cause
of problems often lies closer to home.
The Five Whys Technique
When looking to solve a problem, it helps to begin at the end result, reect on what caused
that, and question the answer ve times.3 This elementary and often effective approach to
problem solving promotes deep thinking through questioning, and can be adapted quickly
and applied to most problems.4 Most obviously and directly, the Five Whys technique
relates to the principle of systematic problem-solving: without the intent of the principle,
the technique can only be a shell of the process. Hence, there are three key elements to ef-
fective use of the Five Whys technique: (i) accurate and complete statements of problems,5
(ii) complete honesty in answering the questions, (iii) the determination to get to the bot-
1 Inputs, activities, and outputs are within the direct control of an intervention’s management. An outcome is
what an intervention can be expected to achieve and be accountable for. An impact is what an intervention is
expected to contribute to.
2 Results-based management is a life-cycle management philosophy and approach that emphasizes results in
integrated planning, implementing, monitoring, reporting, learning, and changing. Demonstrating results is
important for credibility, accountability, and continuous learning, and to inform decision-making and resource
3 Five is a good rule of thumb. By asking “why” five times, one can usually peel away the layers of symptoms that
hide the cause of a problem. But one may also find one needs to ask “why” fewer times, or conversely more.
4 Root cause analysis is the generic name of problem-solving techniques. The basic elements of root causes
are materials, equipment, the man-made or natural environment, information, measurement, methods
and procedures, people, management, and management systems. Other tools can be used if the Five Whys
technique does not intuitively direct attention to one of these. They include barrier analysis, change analysis,
causal factor tree analysis, and the Ishikawa (or fishbone) diagram.
5 By repeating “why” five times, the nature of the problem as well as its solution becomes clear.
tom of problems and resolve them. The technique was
developed by Sakichi Toyoda for the Toyota Industries
The Five-Whys exercise is vastly improved when applied
by a team and there are ve basic steps to conducting it:
Gather a team and develop the problem statement in
agreement. After this is done, decide whether or not
additional individuals are needed to resolve the prob-
Ask the rst "why" of the team: why is this or that problem taking place? There will probably be three
or four sensible answers: record them all on a ip chart or whiteboard, or use index cards taped to a wall.
Ask four more successive "whys," repeating the process for every statement on the ip chart, white-
board, or index cards. Post each answer near its "parent." Follow up on all plausible answers. You will
have identied the root cause when asking "why" yields no further useful information. (If necessary,
continue to ask questions beyond the arbitrary ve layers to get to the root cause.)
Among the dozen or so answers to the last asked "why" look for systemic causes of the problem. Discuss
these and settle on the most likely systemic cause. Follow the team session with a debrieng and show
the product to others to conrm that they see logic in the analysis.
After settling on the most probable root cause of the problem and obtaining conrmation of the logic
behind the analysis, develop appropriate corrective actions to remove the root cause from the system.
The actions can (as the case demands) be undertaken by others but planning and implementation will
benet from team inputs.
Five Whys Worksheet
Why is that?
Define the problem:
Why is it happening?
Why is that?
Why is that?
Why is that?
For Want of a Nail
For want of a nail the shoe is lost;
For want of a shoe the horse is lost;
For want of a horse the rider is lost;
For want of a rider the battle is lost;
For want of a battle the kingdom is lost;
And all for the want of a horseshoe nail.
—George Herbert
Source: Author
Five Whys Technique
The Five Whys technique has been criticized as too basic a tool to analyze root causes to the depth required
to ensure that the causes are xed. The reasons for this criticism include:
The tendency of investigators to stop at symptoms, and not proceed to lower-level root causes.
The inability of investigators to cast their minds beyond current information and knowledge.
Lack of facilitation and support to help investigators ask the right questions.
The low repeat rate of results: different teams using the Five Whys technique have been known to come
up with different causes for the same problem.
Clearly, the Five Whys technique will suffer if it is applied through deduction only. The process articu-
lated earlier encourages on-the-spot verication of answers to the current "why" question before proceeding
to the next, and should help avoid such issues.
Further Reading
ADB. 2007. Guidelines for Preparing a Design and Monitoring Framework. Manila. Available: www.adb.
――. 2008a. Output Accomplishment and the Design and Monitoring Framework. Manila. Available:
――. 2008b. The Reframing Matrix. Manila. Available:
――. 2009a. Monthly Progress Notes. Manila. Available:
――. 2009b. Assessing the Effectiveness of Assistance in Capacity Development. Manila. Available:
Jeff Bezos and Root Cause Analysis
[The author explains how while he worked for in 2004 Jeff Bezos did something that the author still
carries with him to this day. During a visit the Fulllment Centers, Jeff Bezos learned of a safety incident
during which an associate had damaged his nger. He walked to the whiteboard and began to use the Five Whys
Why did the associate damage his thumb?
Because his thumb got caught in the conveyor.
Why did his thumb get caught in the conveyor?
Because he was chasing his bag, which was on a running conveyor.
Why did he chase his bag?
Because he had placed his bag on the conveyor, which had then started unexpectedly.
Why was his bag on the conveyor?
Because he was using the conveyor as a table.
And so, the root cause of the associate’s damaged thumb is that he simply needed a table. There wasn’t one around
and he had used the conveyor as a table. To eliminate further safety incidences, needs to provide tables
at the appropriate stations and update safety training. It must also look into preventative maintenance standard work.
Source: Adapted from Shmula. 2008. Available:
Asian Development Bank
ADB, based in Manila, is dedicated to reducing poverty in the
Asia and Pacific region through inclusive economic growth,
environmentally sustainable growth, and regional integration.
Established in 1966, it is owned by 67 members—48 from the
region. In 2007, it approved $10.1 billion of loans, $673 million of
grant projects, and technical assistance amounting to $243 million.
Knowledge Solutions are handy, quick reference guides to tools,
methods, and approaches that propel development forward and
enhance its effects. They are offered as resources to ADB staff. They
may also appeal to the development community and people having
interest in knowledge and learning.
The views expressed in this publication are those of the author
and do not necessarily reflect the views and policies of the
Asian Development Bank (ADB) or its Board of Governors or the
governments they represent. ADB encourages printing or copying
information exclusively for personal and noncommercial use with
proper acknowledgment of ADB. Users are restricted from reselling,
redistributing, or creating derivative works for commercial purposes
without the express, written consent of ADB.
Asian Development Bank
6 ADB Avenue, Mandaluyong City
1550 Metro Manila, Philippines
Tel +63 2 632 4444
Fax +63 2 636 2444
For further information
Contact Olivier Serrat, Head of the Knowledge Management Center, Regional and Sustainable Development Department,
Asian Development Bank (
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