Transcript Cause & Effect Diagrams

Cause & Effect Diagrams
Scott Davis
QI Coordinator
Tacoma Pierce County Health Department
Recorded 6-12-12
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Objectives
Understand …
– Purpose of the CED
– Elements of the CED
– How to construct a CED
CEDs
When would I use this tool?
Most often: Late in the analysis phase when you want
to develop theories of cause
You might also use it …
– In assessment phase…to i.d. key drivers of an issue
– Early in analysis phase…to organize stratification
– In change phase…to consider solution options
Any time you consider how multiple factors might
contribute to a specific phenomenon
Analysis Tool:
Cause & Effect Diagram
Effect Statement
(as specific and measurable
as possible)
Theory of cause
Specific theory
of cause
Cause Category
“Fishbone” Format
(Aishikawa)
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Effect Statement
Examples
Outside referrals take more than a week to process.
The data input step takes 3 to 5 hours.
34% of request forms are sent back.
Why does printing permits take so long?
Analysis Tool:
Cause Typical
& Effect
Diagram
Cause Categories
Machines
Methods (process)
Materials
Milieu (Environment)
Men
(people)
Measurement
OR: Brainstorm causes on Post-It Notes
and then group in natural affinities (see
affinity diagram)
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Analysis Tool:
CED High-level Flow Format
High-level
Process
Step 1
High-level
Process
Step 2
High-level
Process
Step 3
Theory of
cause
Sub-theory
of cause
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High-level
Process
Step 4
Effect Statement
(as specific and
measurable as
possible)
Analysis Tool:
“Why” Root Diagram Format
Why?
Why?
Why?
Cause Category
Effect Statement
As specific and
measureable as
possible
Cause Category
Specific Theory
Theory
Theory
Cause Category
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Analysis Tool
Centric CED Format
Cause
Category
Theory
Cause
Category
Specific
Theory
Effect
Statement
Cause
Category
Cause
Category
Cause
Category
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Analysis Tool:
Cause & Effect Diagram
Steps
Write specific effect statement.
(Usually, but
not always, more specific than your original problem
statement)
Determine format
Determine cause categories/steps
Brainstorm theories of cause for each
category
Keep asking “why?”
When complete, determine top 2-3 causes
worth testing/investigating
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