Thinking Tools - For Root Cause Analysis
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Transcript of Thinking Tools - For Root Cause Analysis
T h e o r y o f C o n s t r a i n t s T h i n k i n g To o l s
ROOT CAUSE ANALYSIS WORKSHOP
Presented by Kelsey van Haaster and Tavis Ashton-Bell
OVERVIEW
Very Brief intro to the Theory of Constraints ( 5 minutes)
A worked example of a Current Reality and a Future Reality Tree (15 minutes)
Introducing the ToC thinking tools (5 minutes)
Step by step practice on a problem of your choosing - (Team activity) (20 minutes)
Sharing back to the group (10 minutes)
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A VERY BRIEF INTO TO THE THEORY OF CONSTRAINTS
Developed by Dr Eliyahu Goldratt, Physicist and Management Specialist
Author of The Goal, Beyond the Goal and It’s not luck
A philosophy which seeks to understand a system through the identification of cause and effect
Applicable in any domain
ToC thinking tools are based on this philosophy and:
Are both systemic and systematic in approach
Produce robust, logically sound analysis and solutions
What to change
What to change to
How to change
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BENEFITS
Using a picture takes the focus off expertise level and promotes teamwork and common understanding. A CRT provides a visual thought process that can easily be scrutinised for validity and edited for increased buy-in of the problem & priority. Can uncover unrecognised needs. Gets you started on the one thing that has the most impact on the system as a whole
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NOTATION (SIMPLIFIED SUBSET)
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UDE
Undesirable effect
Precondition
Current Reality Tree
Precondition
Future Reality Tree
DE
Desirable effect
IE
Intermediate effect
Action
Action
Goal
Goal
Edge
AND operator
Both
Solution
Solution
THE PROBLEM WITH SOFTWARE PROJECTS
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Relevant undesirable effects and a precondition
The Problem to solve
A WORKED EXAMPLE - BUILDING THE TREE (1)
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Which of our UDE (s) explain the problem ?
Clarity Reservation Is the cause and effect relationship clear?
Entity Existence Reservation Do the cause and effect entities really exist?
Causality Existence Reservation Is the causal link valid?
Predicated Effect Existence Reservation there is no other effect which negates this one being cause
Insufficient Cause Reservation An additional non trivial cause must exist to explain the observed effect
Additional Cause Reservation - Neither cause can account for the effect alone
Tautology - A cause and effect relationship is redundant
Add the contributing UDE’s and apply the categories of
legitimate reservation
WORKED EXAMPLE - BUILDING THE TREE (2)
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Add the contributing UDE’s and apply the
categories of legitimate reservation
FINDING THE SOLUTION
The generation of or more solutions are accomplished using the concept of the Cloud.
The underlying assumption behind the concept of the Cloud is that there are no conflicts in nature – only erroneous assumptions.
The cloud provides a structured approach to identifying and then testing underlying assumptions.
A quick example: Asking for a pay rise
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BACK TO OUR PROBLEM
There are many potential solutions, however lets use a widely understood one to demonstrate the Future Reality Tree as a way of testing and presenting the idea
First the solution:
We are uncovering better ways of developing software by doing it and helping others do it.
Through this work we have come to value:
Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan
That is, while there is value in the items on the right, we value the items on the left more.
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BUILDING A FUTURE REALITY TREE
At its simplest level an FRT is a CRT with all the Undesirable Effects transformed into Desirable Effects and the problem statement turned into a goal.
We Build an FRT by injecting our solutions into our Current Reality Tree and evaluating whether the solution transforms Undesirable Effects into Desirable ones.
This usually requires some refinement and rewording as you go
Let’s try this with our example problem
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THE COMPLETED TREE
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We are uncovering better ways of developing software by doing
it and helping others do it.
Through this work we have come to value:
Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan
THE TOOLSET
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Tool When to use
Current Reality Tree To understand the root cause(s) of the problem
When there is disagreement about the nature of the problem
When there is disagreement about the extent of the problem
Evaporating Cloud (injection) To resolve conflict To gain agreement about
the nature of a solution
Future Reality Tree To identify a solution To ensure the solution addresses the whole problem
To test the logic behind a solution
Pre-requisite TreeTo identify the pre- conditions for implementing a solution
Transition TreeTo identify the steps required to implement a solution
PROOF READING TOOLS FOR YOUR TREES
Clarity Reservation Is the cause and effect relationship clear?
Entity Existence Reservation Do the cause and effect entities really exist
Causality Existence Reservation Is the causal link valid
Predicated Effect Existence Reservation
Showing that the cause does not result in the initial effect by using another effect
Insufficient Cause Reservation An additional non trivial cause must exist to explain the observed effect
Additional Cause Reservation Neither cause can account for the effect alone
Tautology A cause and effect relationship is redundant
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Categories of Legitimate Reservation Intended to raise valid concerns about cause and effect rigour, without
raising resistance of defensiveness with others
NOW IT’S YOUR TURN
Work in groups of 2 - 4 and create a Current Reality Tree for a problem of your choosing.
You can use sticky notes on a whiteboard, or any software that lets you draw boxes and line.
e.g. Powerpoint, Keynote, Word, even paint
Use the cheat sheet to follow the steps and we will be on hand to help.
At about 10 minutes before the end of the session, we will ask people to share the problem they looked at and any new insights gleaned from the process.
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REFERENCES AND RESOURCESBooks: ToC in General
The Theory of Constraints - E. Goldratt
The Goal: A process of Ongoing Improvement
Critical Chain
Books - ToC Thinking Tools
Isn’t it Obvious
It’s Not Luck
Necessary But Not Sufficient
Thinking for a Change
Web Resources
Thinking for a Change handout - (pdf)
ToC Thinking tools - Wikipedia link
A very comprehensive guide to implementation from Kelvyn Youngman
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