Tools to Achieve Performance Excellence
A Thoughtful Approach to Root
Cause Analysis
Andrew Kirsch
Master Black Belt
Enterprise Excellence
ECOLAB
Two Philosophical Assumptions
We all experience
a shared Reality
All effects are
caused
Three Imperfect Definitions
• Effect - A change in a state of being that results
when something is done, or happens, or does not
happen.
• Cause – Something that contributes to producing an
effect
• Root Cause – One or a few of the most fundamental
of a chain of causes that product an effect
5 Why’s and the Washington Monument
Problem: Washington Monument required frequent,
very expensive repairs.
1. Why?
Frequent washing was damaging the monument.
2. Why did it need to be washed so much?
Pigeon droppings
3. Why were the pigeons on the monument?
To eat the spiders
4. Why were there spiders on the monument?
To eat the insects
5. Why were the insects there?
They are attracted to the brightly lit surface at
sunset.
A Template for 5 Why Analysis
Effect of Interest:
1. Why?
2. Why?
3. Why?
4. Why?
5. Why?
Tips for Use:
1. There is nothing magic about 5, but push yourself to go further than 1 or 2
2. At some point you may find yourself going from the specific to the general
(poor communication, political gridlock, lack of motivation) - back up and
try to be more specific
Cause and Effect Diagram
(Also called Fishbone or Ishikawa Diagram)
Effect of
Interest
Categories of
Causes
Represents the relationship between an effect
(problem) and its potential causes where
causes are organized by categories
Cause and Effect Diagram
• Why - Use of categories ensure a full range of potential
causes have been considered
• Overcome the “theme effect” by allowing the group to see the
categories into which their ideas fall and dig deeper on those
with fewer items
• How – Decide on a set of major categories before
starting to brainstorm causes
• The traditional categories for manufacturing are personnel,
environment, machines, materials, methods, measurements
• For non-manufacturing use, might use the 4 Ps: Place,
Procedures, People, Policies
Blending Fishbone and 5 Why Methods
The 5 Why method is often used with a Cause and Effect Diagram to drill down to a
root cause
Effect: Cost of maintaining test kits for field employees
too high
1. Why? Must frequently replace reagents in the kits
2. Why? The reagents are past expiration date
3. Why? The shelf life of many of the
reagents are a year or less
Effect: Same
1. Why? Have to pay a high price for the
reagents in the quantities needed
2. Why? xxxxxxxxxxxxx
3. Why? xxxxxxxxxxxxxxxxxxx
4. Why? xxxxxxxxxxxxxxxxxx
5. Why? xxxxxxxxxxxxxx
4. Why? At the time that the shelf lives
were determined, the software for
recording the official shelf life only had
two choices in the pulldown menu – 6
months and 12 months!
Corrective Action = Qualify and
document a longer shelf life where
possible
Limitations of a Simplistic Analysis
1. An effect may require two or more causes to
occur in the same place and time
2. The analysis may be limited by the current
level of knowledge
3. The analysis may be based on conventional
wisdom or restricted by prejudice
4. The root cause may not be the easiest to fix
5. An effect may be part of a system “loop”
A Template for Two or More Causes per
Level (per Why)
Effect
1st Level Why
2nd Level Why
3rd Level Why
Cause 1
Cause 1.1
Cause 1.1.1
Cause 1.1.2
Cause 1.2
Cause 1.2.1
Cause 1.2.2
Cause 2
Cause 2.1
Cause 2.1.1
Cause 2.2.2
Cause 2.2
Cause 2.2.1
Cause 2.2.2
Cause 3
Cause 3.1
Cause 3.1.1
Cause 3.1.2
Cause 3.2
Cause 3.2.1
Cause 3.2.2
Two or More Causes per Level (per Why)
Effect
1st Level Why
2nd Level Why
3rd Level Why
Worker hurt
his hand and
shoulder by
slipping on a
wet floor,
while
walking
through an
area not
intended for
foot traffic
Cause 1
The floor was wet
Cause 1.1 The drain
was not working
Cause 1.1.1 Plugged
Cause 1.2 The vessel
had to be rinsed
Cause 1.2.1 SOP requires
Cause 2.1 The shoes
were 5 years old
Cause 2.1.1
Cause 2.2 The shoes
hadn’t been replaced
Cause 2.2.1 Thought ok
Cause 3.1 Alternate
route takes longer
Cause 3.1.1 Plant design
Cause 3.2 No barrier
to prevent
Cause 3.2.1 Not expected
Cause 2
The worker’s shoes
had poor tread
Cause 3
The worker chose to
go through this area
Cause 1.1.2 Not checked
Cause 1.2.2
Cause 2.2.2
Cause 2.2.2 Busy
Cause 3.1.2
Cause 3.2.2
Considerations beyond Root Cause
• Tradeoffs
• Span of Influence or Control
• Legality, Propriety, Respectfulness
Two or More Causes: Reconsidering the
Washington Monument
Problem: Washington Monument repairs.
1. Why?
Frequent washing was damaging the monument.
2. Why did it need to be washed so much?
Pigeon droppings
3. Why?
Pigeons AND a food source (spiders)
4. Why?
A nearby population of pigeons
Spiders AND a food source (insects)
5. Why?
A nearby population of spiders
A nearby population of insects
Attraction for the insects (brightly lit surface).
5 Why for an Act of Gang Violence
+
Member of
Gang A Hurt
by B
Gang B Wants
Revenge
+
Gang A Feels
Violated
+
+
Gang B Feels
Violated
+
Gang A Wants
Revenge
Member of
Gang B Hurt
by A
+
Role of Evidence/Data
• Makes all the difference between
“conventional wisdom” and sound analysis
– A single instance is not strong proof of root cause
• Each link in the chain of causes should be
verified with evidence/data
– Physical scientific studies (e.g. chemical analysis)
– Statistical studies (e.g. clinical trials)
– Behavioral studies (e.g. Hawthorne effect)
– Historical data review (e.g. drunk driving)
– Is/Is Not analysis
Is/Is Not Analysis
• Consider the what, where, when, extent of
the problem/deviation:
– What specific object has the
problem/deviation?
– What is the nature of the problem/deviation?
– What similar object could have the
problem/deviation but does not?
– What other problems/deviations might
reasonably be observed but are not?
• Test if possible causes against the is and is
not facts to rule out some, judge likelihood
IS
IS NOT
Boiling it down …
1. Start with a fishbone diagram to enlarge your view
of possible causes
2. Use the 5 Why approach to go deep
–
–
–
Be open to multiple causes at each level
Use simple (linear) 5 Why when possible
Be open to a system loop
3. Look for data to support the chain of causes
4. Decide on the root cause(s)
–
–
Give preference to prevention at that cause
Factor in tradeoffs, span of influence, etc. as appropriate
Summary of Tools Discussed
• Fishbone Diagram
• 5 Why (Simple and Multiple Cause)
• Systems Thinking (the Loop)
– See Peter Senge, “The Fifth Discipline”
• Is/Is Not Analysis
– See Charles Kepner and Benjamin Tregoe, “The
New Rational Manager”
QUESTIONS?