freeleansite.com root cause analysis - overview root cause analysis and corrective action (rcca)
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Root Cause Analysis - Overview
Root Cause Analysis and Corrective Action
(RCCA)
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RCCA - Learning Objectives
The purpose of this module is to:
• Apply the “5-why” technique in problem solving analysis.
• Identify and understand the direct, contributing and root cause of a problem.
• Learn the 2 types of corrective action.
• Utilize a Corrective Action Matrix form to track and drive action item completions.
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Root Cause Analysis - An Overview
Root Cause Analysis and Corrective Action (RCCA) is a process for :
• Finding the true cause(s) of an event• Identifying and implementing
corrective actions• Assessing the effectiveness of
corrective actions• Preventing recurrence of the events
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Why Root Cause Analysis ?
Integral part of Continuous Improvement
If we do not take action on problems,we will be wasting our time and all involvedwill lose interest.
• Our Customers expect it !• ISO 9001-2000 requirement• Makes good Business sense• Keeps us from passing on problems to internal and external CUSTOMERS
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DMAIC process applied to RCCA
Measure
Form Team Scope project
AnalyzeInvestigate Root Cause
Control –Standardize
Improvement
Quantify Problem
MakeImprovement
RCCA
(Customer complaints, Audit findings, Production, Inspection Data, Product returns, Warranty etc)
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Understand and State the Problem
• Understand the Problem• From the event, what is the problem to be solved, or what is the customer’s concern?
• More than one Problem?• An event could have more than one problem, with a root cause for each problem.
If you cannot say it simply, you do not understand the problem!
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A Cause . . .
Is a set of circumstances or conditions that:
• Allows a condition to exist or an event to happen,
Or
• Makes a condition exist or an event happen
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The Critical Five
Direct Cause: The cause that directly resulted inthe event.(The first cause in the chain.)
Contributing Cause: The cause(s) that contributed to an
event but, by itself, would not have caused the event.
(The cause after the direct cause.)
Root Cause: The fundamental reason for an event,
which if corrected, would prevent recurrence.(Last cause in the chain.)
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The Critical Five
Specific Corrective Action: Action(s) taken to correct or
improve conditions noted in the event, by changing the
direct cause or,The direct cause and the effect.
Preventative Corrective Action: Action(s) taken that
prevent recurrence of the condition noted in the event.
(Preventive actions must directly address the root and
contributing causes to be effective.)
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Root Cause/ Corrective Action
The process requires complete honesty and no
predetermined assumptions.
Follow the Data! Don’t try to lead it.
A common cop-out: “Operator error…” Why do people not comply?
• Improper instructions• Worn-out tools• Improper training• Lost expectations
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Root Cause/ Corrective Action
Don’t limit the search !
• What role did management systems play?• Are you looking beyond your own backyard?• Remember the 80/20 rule.
Be attentive to causes that show up frequently!
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Root Cause/ Corrective Action
Utilize 5 Why’s technique for determination of cause and effect… Ask “Why?” 5 times.
Most problems, even the most serious or complex, can be handled by using the 5 Why technique when coupled with cause chain diagrams.
So, why use the 5 Why technique?
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Root Cause/ Corrective Action
Just keep asking …
Why did it happen?
• Didn’t get to work on time. …… Why?• Car wouldn’t start. …… Why?• Battery was dead. …… Why?• Dome light stayed on all night. …… Why?
Kids played in car, left door ajar. ….. Why?
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Root Cause/ Corrective Action
The 5 Why’s … another example –
Problem: “Customers complain about waiting too long to get connected to staff during lunch hours.”
Why does the problem happen?• Backup operators take longer to connect callers.
Why does it take backup operators longer?• Backup operators don’t know the job as well as the regular
operator/ receptionist do.Why don’t backup operators know the job as well?
• There is no special training, no job aids to make up for the gap in experience and on-the-job learning for back-ups.
Why don’t they have special training or job aids?• In the past, the organization has not recognized this need.
Why hasn’t the organization recognized the need?• The organization has no system to identify training
needs.
freeleansite.comOperators poorlytrained?
Large volume of rework in PCB manufacture
Poor control ofmanuf. process
Didn't understandimplications of spec.
They rely upon100% inspection
Didn't achievespec. first time
Boards difficultto make
Operators makelots of mistakes
Operations take noresponsibility fortheir work
They're designedlike that
Don't know how tocontrol the process
The designs havebeen throughseveral iterations
• What it is:– Involves the use of
tree structures to break down the area/process under study
– A tree diagram where all items are included (comprehensively exhaustive) and not repeated (mutually exclusive)
• When to use it:– Can be used as an
analysis structure
• Benefits:– Depicts a single
dimension of hierarchy
Decomposition Diagram
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… suited to both Repetitive and Non-Repetitive Processes
Problem Why? Why? Why? Why? Why?
Large volume of rework in PCB manufacture
Poor control of manufacturing process
Boards difficult to make
Operators make lots of mistakes
Don't know how to control the process
They're designed like that
Operators take no responsibility for their work
Operators poorly trained?
They rely upon 100% inspection
The designs have been through several iterations
Didn't achieve spec. first time
Didn't understand implications of spec.
“Why - Why” (5 Why’s) Analysis
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• What it is: – A combination of a decomposition diagram and cause and effect diagram in tree
diagram format that shows the linkages between an effect and its root cause
• When to use it:– When a cause and effect diagram has been built and the primary causes have
been identified, the 5 whys is used to delineate the causal linkages between the final effect and the originating root cause. ** Don’t be limited to only 5 whys: the end point is the root cause
• Benefits:– Establishes the evidence chain (or the hypothesis thereof) so that confirming
facts and data can be collected to substantiate the sequence and the critical dependencies between relationships and time sequences
– Disciplines the problem solving team to critically examine assumptions and evidence in order to support the relationships between each link. “How do you know??”
“Why - Why” (5 Why’s) Analysis
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Why - Why Diagram
MACHINEBROKEN
Misuse
Waiting too long
Too slow
Wrong machine
No budget
No plan
No trainer
No plan to replace
No perceived need
No one responsible
Non-business
Wrong type machine
Deadlines
Not obvious needed
No one responsible
Impatience
Not trained
No budget
"Old reliable"
Too many copies
No limits
WHY?
Age
Overuse
WHY?
WHY?
Case of a Broken Photocopier
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Root Cause/ Corrective Action
Direct Cause: The cause that directly resulted in theevent.(The first cause in the chain.)THIS IS THE ANSWER TO YOUR FIRST QUESTION. (YOUR PROBLEM
STATEMENT)
Contributing Cause: The cause(s) that contributed to an
event but, by itself, would not have caused the event.(The cause after the direct cause.)Note: For a simple problem there may not be any contributing causes.
Root Cause: The fundamental reason for an event,which if corrected, would prevent recurrence.(Last cause in the chain.)
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The Cause Chain
Contrib.Cause
Cause
Root
RCCA
Contrib.Cause
DirectCause
EVENT
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Root Cause Analysis
Let’s expand on a problem … Cause and Effect
Received ticket for safety violation- Car exhaust too loud
- Muffler knocked loose from tailpipe- Daughter hit pot hole
- Pot holes in road- Winters damage roads
- Congress won’t approve extra money for better roads
- Congress doesn’t have extra money- Congress spend money on pork barrels
- Too many lawyers in Congress
Solution? Drive in Sweden, where there are fewer Lawyers.
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Utilize appropriate toolset with the team. Uncover the root cause. Test and formulate corrective action.
Examples:• Brainstorming, Pareto analysis, Cause and Effect
analysis, X-Y matrix• Process audit, Benchmarking• Consensus, mistake proofing (poka-yoke)• Statistical analysis, quality function deployment • Opportunity for simplification - Integration and standardization (refer to VE & VA module)
Root Cause Analysis
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Root Cause/ Corrective Action
Corrective Action:
A set of planned activities (actions) implemented for the sole purpose of permanently resolving the problem.
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Root Cause/ Corrective Action
Two types of Corrective Action:
• Specific• Preventive
These two types of corrective action are quite different in how they are applied and what they do. Not understanding this leads to serious mistakes in fixing problems.
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Root Cause/ Corrective Action
Specific Corrective Action:
Action(s) taken to correct the direct cause. (Corrects, or improves the condition noted
in the event, by changing the direct cause, or the
direct cause and effect.)
• Sometimes called containment• Only used to correct the DIRECT cause• Does not prevent recurrence !
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Root Cause/ Corrective Action
Preventive Corrective Action:
• Preventive corrective actions focus on changing
the root cause and any contributing cause(s).
• You probably won’t get a 100% effective fix at just one point (the root cause).
• You often have to consider two or more contributing causes to ensure the chain is broken.
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Root Cause/ Corrective Action
Preventive Corrective Action:
• Action(s) taken prevent recurrence of the condition noted in the event. (Preventive
actions must directly address the root and contributing causes to be effective.)
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Preventive Corrective Action
Contrib.Cause
Cause
Root
Contrib.Cause
DirectCause
EVENT
X
X
X
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Root Cause/ Corrective Action
Test the specific solutions to ensure they are valid:
• Do the corrective actions eliminate or control the direct cause?
• Are the results desirable?
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Root Cause/ Corrective Action
Example (ask Team)
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Root Cause/ Corrective Action
Preventive Action Test:
• If these preventive corrective actions were in place, would the event have occurred?
• Are there adverse effects caused by implementing the corrective actions that make them undesirable?
• Do the preventive corrective actions lower the risk factor of the event to an acceptable level?
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Root Cause/ Corrective Action
Basic elements of reporting:
• Restatement of the problem/ event/ objective
• Data (who, what, where, why, how, etc.)• Team (natural work group, qualified)• Causes (root, direct, contributing)• Corrective Actions (specific, preventive,
plant-wide)• Milestone dates (Analysis complete, C/A
initiated, C/A implemented, Corrective Action Report closed)
• Follow Up (Is implementation, solution acceptable?)
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Tracking Form - example
Basic tracking form – Corrective Action Matrix (CAM)
Refer to - webpage (tools)
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Tracking Form - example
Watson - Weekly Update
For w/e - FRIDAY 4/22/2005Date Entered into Matrix Location Actions Resp
StartDate
1Teach 2 Yellow Belt Training Sessions (usually offer 3 a year for new Dallas based employees)
1/31/2005 LCSchedule. Plan and
conduct YB training classJW 01/15/05
DallasSet up
room/arrangementsJW 01/15/05
DallasSent out invitations to
DallasJW 01/29/05
1a Dallas CONDUCT 1st CLASS JW 02/10/05
1b Dallas CONDUCT 2nd CLASS JW 02/24/05
BEGAN assembly of YB MASTER LISTING at Corporate 16-Feb DallasAssembly list, review to
existing databaseJW 02/18/05
28-Feb DallasSet up
room/arrangementsJW 02/28/05
28-Feb DallasSent out invitations to
DallasJW 02/28/05
1c 25-Feb Dallas CONDUCT 3rd CLASS JW 02/28/05
4-Mar Dallas Evaluate Performance JW 02/28/05
1d 4-Mar Dallas CONDUCT 4th CLASS JW 02/28/05
4-Mar Dallas Evaluate Performance JW 02/28/05
NOTE: Blank form located on free lean site
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Root Cause/ Corrective Action
Follow-up
A review must be conducted in sufficient detail to assess whether the corrective actions that have been implemented are effective as implemented and are truly preventing recurrence of the event.
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Root Cause/ Corrective Action
Effectiveness Measures
The criteria used to evaluate if the corrective actions achieved the desired outcome.
Examples:• Scrap quantities significantly reduced• Print was not manufactured to print tolerance. After
corrective action, part meets print.• Design could not be manufactured with current technology.
After corrective action, part can be manufactured with current technology.
• Parts would not assemble properly. After corrective action, parts would assemble properly.
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Root Cause/ Corrective Action
Did corrective actions work?
Some additional things to consider:
• If corrective action implemented differs from proposed, find out why.• If better or alternate corrective actions were implemented,
document the changes.• Periodic checks may be necessary to be sure the corrective
actions are still in place.• Document using the proper forms.
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Root Cause Analysis - Overview
Root Cause Analysis and Corrective Action
(RCCA)