1Quality Tools

Root Cause Analysis

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Root Cause Analysis

Module OutlineChronic vs. Sporadic Problems Improvement (Breakthrough) vs. TroubleshootingAddressing Chronic Problems - Breakthrough

DefinitionsDiagnosisWhy “Root Cause”?Tie to MBF (Management by Fact)

Addressing Sporadic Problems - Troubleshooting SummaryResources

?

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Root Cause Analysis

Module Objectives You will be able to:• Distinguish between chronic vs. sporadic

problems.• Define Problem/Symptoms/Causes/Diagnosis.• Describe approaches to find root causes of chronic

problems.• Describe the link between Root Cause Analysis

and MBF.• Describe approaches to find root causes of

sporadic problems.

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Root Cause Analysis

Improvement vs. Fire FightingPe

rfor

man

ce

Good

BadSporadic

ChronicGain

Time

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Root Cause Analysis

Chronic Problems• Existed for some time• Usually “lived with” or accepted• Cost more $$$$$ than sporadic problems• Don’t sound alarms (allowances for problem have

been made in the system)• Competitors may be enduring same losses• Improvement is needed when a chronic problem

is occurring• Requires improvement PROJECTS - investment

of time and resources• Fire Prevention - attack the chronic level

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Root Cause Analysis

Sporadic Problems• A “spike” in performance• “Alarm” usually goes off• Troubleshooting used when a sporadic problem

happens (a departure from the normal level)• Aimed at restoring the status quo• May include Interim (temporary) fixes• Corrective Action - eliminate the cause of the

problem• Remove the change that produced the deviation or

new change to offset deviation• Fire Fighting - focus on control

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Root Cause Analysis

Improvement vs. TroubleshootingImprovement: Focused on attaining a new level

of performance that is superior to any previous level.

• Accomplished through BREAKTHROUGH.• Improves chronic level of performance.• Fire Prevention

Troubleshooting: Focused on solving a sudden change in performance.

• Accomplished with CORRECTIVEACTION to put out a fire.

• Improves sporadic level of performance.• Fire Fighting

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Root Cause Analysis

Sequence for Breakthrough•Proving the need•Identifying Projects•Organizing project teams•Establishing project

(mission/vision/responsibilities)•Diagnosis - to find the causes•Developing remedies - based on knowledge of the causes•Proving remedies & effectiveness - under operating conditions•Dealing with resistance to change•Controlling at the new level

Set-

upC

arry

-out

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Root Cause Analysis

DefinitionsProblem: Any deviation from the standard,

expected, or desired which is outside the accepted tolerance, norm, or benchmark.

Project: a problem scheduled for solution!Symptom: An observable indicator, cue, or event

directing attention to a problem. Arising from and accompanying a problem.

Theory: Unproved assertion as to reasons for the problem and symptoms.

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Root Cause Analysis

Definitions - ContinuedCause: “Something” that happened to produce a

deviation of the actual from the expected or desired. Proved reason for existence of problem. Often “multiple causes”.

Dominant or Root Cause: a major contributor to existence of problem which must be fixed before there is an adequate solution.

Remedy: a change that can successfully eliminate or neutralize the cause of a problem.

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Root Cause Analysis

Definition - DiagnosisDiagnosis: the process of studying symptoms,

theorizing as to causes, testing theories, and discovering causes.

• Diagnosis - to find the causes• Diagnostic Journey = “symptom to

cause”• Followed by Remedial Journey =

“cause to remedy”• “Symptom to cause” is DIFFICULT!

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Root Cause Analysis

Diagnosis for ImprovementDiagnostic Journey:1. Study the symptoms surrounding the problem to serve

as a basis for theorizing about causes.2. Theorize the causes of these symptoms.3. Collect data and do analysis to test the theories and

determine the causes.

When the problem can be switched on & off

at will - the journey is over!

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Root Cause Analysis

Studying Symptoms• Two forms of “Evidence”:

1. Words/documentation describing problem2. Physical measurements & analysis of product/process

• Agreement on “terms/descriptions” for symptoms• Recording data - established to test specific theories• Quantifying symptoms:

•Frequency•Intensity

• Use of Pareto Charts/Analysis

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Root Cause Analysis

Tools for Symptoms

Scratches IIII II II IIII I 15Runs IIII IIII IIII IIII IIII I IIII IIII 34Dirt IIII I IIII 11Wrong Color IIII I I 7Paint Peeling I I 2

Total 32 15 22 69

Problem TotalOrder 1 Order 2 Order 3

• Check Sheets• Concentration Diagram• “Autopsies”

• “Glossaries” for symptom terms

• Pareto AnalysisCheck Sheet Example:

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Root Cause Analysis

Theorizing Causes• Diagnosis is made theory by theory• Need to affirm or deny the validity of theories• This is “IDENTIFYING POTENTIAL CAUSES”• 3 Steps

1. Generate Theoriese.g. Brainstorm, Ask Why 5 times

2. Arrangement of Theoriese.g. Matrix, Tables, Cause & Effect Diagrams

3. Choosing Theories to be Testede.g. Data Collection, Pareto Analysis

• Establish Priorities for testing theories

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Root Cause Analysis

• Ask Why 5+ times• Brainstorming*• Cause & Effect Diagrams*• Force Field Analysis*• Affinity Diagram*• Structure Tree Diagram*• Interrelationship Digraph*• Program Decision Process

Chart (PDPC)*• Matrix Diagram*

• Check Sheet*• Pareto Analysis*• Designed Experiments• ETC.

Tools for Theorizing Causes

* Included in Memory Jogger II

Pareto Chart Example:

34 15 11 7 249.3 21.7 15.9 10.1 2.9

49.3 71.0 87.0 97.1 100.0

0

10

20

30

40

50

60

70

0

20

40

60

80

100

Defect

CountPercentCum %

Per

cent

Cou

nt

Paint Shop Defects

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Root Cause Analysis

Tool Example - Ask Why 5 TimesFailures from Supplier A are 2X the industry average.

There is excessive damage in transit.

Packaging is insufficient.

Packaging specifications are incomplete.

Why?

Why?

Why?

Why?

Real Root Cause

There are no technical specifications for packaging available.

Why?

GenerateTheory:

Follow with Remedy!

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Root Cause Analysis

Tool Example - Cause & EffectGenerate Theory:

Follow with Test of Theories based on priorities

Out of Date

Not Manufacturable

PartProblem

Cutting oilBar Stock

Capability

Scheduling

cpk Tolerances

Procedures

Set-upMaintenance

Cost

Inaccurate

TrainingEngineeringSupport Operator

Errors

Adjustments

Materials Machinery

Methods Manpower

WrongMaterial

OverSized

Wrong Oil

Packaging

PrintInaccurate

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Root Cause Analysis

Tool Example - Structure Tree

ElbowFailures

Crimp makesinadequate contact

Cross Thread

Pin not fullyseated

Cable not fullyseated

DefectiveElbow

Operator

Material

Methods

Tools &Equipment

Guide

Thread

Lack of Verificationfor Alignment

# of Revolutionsnot counted

Problem Subproblems TheoriesMost LikelyRoot Causes

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Root Cause Analysis

Testing Theories to Find Cause• Determine which cause is ROOT cause• Identifying most likely cause• DATA COLLECTION & ANALYSIS!• Methods

1. Product/Process “Dissection”e.g. Flow Map, Process Capability Study, Time to Time

2. Collecting New Datae.g. Measuring within the process

3. Experiments - create & process trials to test validitye.g. Designed experiments, pilots, trials

4. Measure for Diagnosise.g. Variables vs. attributes, increase precision, new

methods

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Root Cause Analysis

• Historical Review• Flow Diagram/Map*• Process Capability Analysis• Time to Time Analysis• Stream to Stream Analysis• Histograms*• Control Charts*• Piece to Piece Analysis• Within Piece to Piece Analysis• Multi-Vari Analysis

• Check Sheet*• Pareto Analysis*• Designed Experiments• Correlation Studies• Measurements within process• Study of Work Methods• Measurement Capability Studies• ETC.

Tools for Testing Theories

* Included in Memory Jogger II

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Root Cause Analysis

Tool Example - Histogram & Run Chart

Test Theory:

Follow with Remedy!

Monthly DPU for Product XYZ

0.00

5.00

10.00

15.00

20.00

25.00

Dec

-97

Feb-

98

Apr

-98

Jun-

98

Aug

-98

Oct

-98

Dec

-98

Feb-

99

Apr

-99

Jun-

99

Aug

-99

Oct

-99

Dec

-99

DPU

Level III Audit DPMU

0

500

1000

1500

2000

2500

3000

6/1/

98

6/3/

98

6/5/

98

6/9/

98

6/11

/98

6/15

/98

6/17

/98

6/19

/98

6/23

/98

6/25

/98

6/29

/98

DPM

U

Histograms:Run

Charts:

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Root Cause Analysis

Tool Example - CapabilityTest Theory: - Structured Experimentation

Follow with Remedy!

• Goal: Collect data on all parts of the process so that:– Capture all contributors to variability– Variability can be partitioned into parts due to each

contributor

=

Total Machine Cavity Time Sample

+ + +

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Root Cause Analysis

Diagnosis of Failures in Systems• Historical Review - objective to improve segment of

system used to attain qualitye.g.: Product Development, Supplier Relations

• Based on analysis of # of past problems• Interview and Document:

1. Brief description of problem2. Stage where problem 1st observed3. Earliest stage at which problem COULD have been discovered4. Reasons for NOT discovering problem at earlier stage5. What could have been done to have found the problem earlier or avoided it completely

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Root Cause Analysis

Diagnosis of Failures in SystemsExamples:1. Historical review of past product development problems:• Symptoms & Cause: Review revealed use of

FMEA/FMECA (Failure Mode, Effect, and Criticality Analysis) would have identified problems upfront.

• Remedy: Require FMEA upfront for new products.

2. Historical review of manufacturing defects:• Symptoms & Cause: Review revealed lack of set-up

procedure led to high lot to lot variation and defects.• Remedy: Document and implement set-up procedure.

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Root Cause Analysis

Diagnostic JourneyRoot Cause AnalysisBegins with Collecting Data on Symptoms

Ends with agreement on Cause(s)

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Root Cause Analysis

Why Find the “Root Cause”?

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Root Cause Analysis

What is MBF Used For? Address gaps in business performance

— Customer Satisfaction— Employee Satisfaction— Business models— Operational processes— Manufacturing processes

Simplify reporting Link problems and root causes with action and

results Link a reporting format to a problem solving model Report on projects that address a specific problem

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Root Cause Analysis

Management by Fact (MBF)

DirectionSetting

DirectionDeployment

ManagementProcess

Policy Deployment &Management by Fact

PolicyDeployment

MonitorPerformance

GapDetected

No

Yes

PRIORITIZ AT ION &ROOT CAUSE

COUNTER M EASURES& ACTIV ITIES

W HO W HEN PROC ESSCAPABILITY

Process and Equipment1.1 1.1

Product Design2.1 2.1

M ethods3.1 3.1

People and Workmanship4.1 4.1

BENCHM ARK

Supplier5.1 5.1

Data Graph Supporting Data Graph

PROBLEM STATEMENT

Remedies

Root Cause AnalysisDiagnosis

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Root Cause Analysis

2. Root Cause Categorization / Analysis (RCA)

AnalyzeProblem

2

•Separate “beliefs” from “real” problem•Determine, categorize, and analyze Root Causes•Use basic quality tools

•Cause and Effect Diagram•Affinity diagram•Ask “WHY” 5 times

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Root Cause Analysis

MBF FormPROBLEM STATEMENT/OBJECTIVES & PERFORMANCE TRENDS: (indicate a brief statement of fact here)

Insert graph of performance over time here (e.g., Pareto Chart / Current State vs. Goal)

Insert graph of more detailed information here (Supportive Info. as necessary - e.g., Costs associated with the problem statement)

PRIORITIZATION & ROOT CAUSE(list the gaps in performance & state the true root cause)

COUNTER MEASURES & ACTIVITIES(enter specific action items, who has ownership and the due date)

WHO WHEN PROCESS CAPABILITY

1. Process and Equipment1.1 (ask the five whys to get to the root cause) 1.1 (solution path should focus on “Breakthrough Improvements”)

(Enter expectedbenefits for eachcounter measurehere.)

(Enter impact of eachcounter measurehere. Compare to seeif target wasachieved.)

2. Product Design2.12.2

2.12.2

3. Methods3.13.23.3

3.13.23.3

4. People and Workmanship4.1

4.1 BENCHMARK

5. Supplier5.15.2

5.15.2

(Use industry benchmarks here compared toour current state)

Root Cause Analysis/Diagnosis

Remedies

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Root Cause Analysis

Troubleshooting• Diagnosis & remedial action applied to

sporadic problems• Generally receives immediate attention• Result of adverse change• Similar to chronic problem journey, but often

simpler• Journey is discovering what the change was

and removing or adjusting for it• Journey: Symptom to Cause to Remedy• If troubleshooting is ineffective, the result

will not be maintained

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Root Cause Analysis

Troubleshooting• Ask: What, Where, When, How Much, Who• Compare Good vs. Bad, time to time, ETC.• Ask what “IS & IS NOT”• Reconstruct time sequence• Take corrective action to remedy the problem• Use a structured approach:

1. State deviation.2. Specify the deviation (is & is not, what, where, etc.).3. Identify unique characteristics of deviation.4. Search for changes.5. Develop possible causes.6. Test the possible causes against the requirement.7. Verify the cause (duplicate or eliminate by removing cause).

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Root Cause Analysis

Summary• Need to distinguish between sporadic & chronic problems• Need to be persistent - get to root cause!• For chronic problems:

•Use BREAKTHROUGH•Use Root Cause Analysis (Diagnosis)

• For sporadic problems - use Troubleshooting• Improvement requires use of multiple quality tools!• To find true (root) causes you need to be a:

•Doctor•Detective•Driver

•Gardner•Firefighter

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Root Cause Analysis

References•Books (+ many others):

– “Quality Planning and Analysis”, J. M. Juran & Frank M. Gryna, Third Edition, McGraw Hill.

– “Juran’s Quality Control Handbook” 4th Edition, McGraw Hill.

– The Memory Jogger II, Michael Brassard & Diane Ritter, GOAL/QPC, 1994.

– Analytic Trouble Shooting, Kepner Tregoe, 3rd Edition, 1978, Princeton Research Press