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Basic Seven Tools of Quality

Cause-and-Effect Diagrams

Flowcharts

Checklists

Control Charts

Scatter Diagrams

Pareto Analysis

Histograms

Cause and Effect Diagram?

Ishakawa Diagram for the inventor, Dr. Kaoru Ishakawa.

It is also known as a Fishbone Diagram or Ishikawa Diagram or

herringbone diagrams or Fishikawa.

The most useful tool for identifying the causes of problems.

Common uses of the Ishikawa diagram are productdesign and

quality defect prevention to identify potential factors causing an

overall effect.

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What is a Cause and Effect Diagram?

A visual tool to identify, explore and graphically display, in

increasing detail, all of the suspected possible causes related to a

problem or condition to discover its root causes.

Not a quantitative tool

Problem/Desired

Improvement

Main Category

Cause

Root Cause

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Causes Effect

Shows various influences on a process to identify most likely root causes of problem

Problem

Main Category

Cause

Sub-C

ause

Root Cause

Cause and Effect Diagram Fishbone

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Why Use Cause & Effect Diagrams? Focuses team on the content of the problem

Creates a snapshot of the collective knowledge of team

Creates consensus of the causes of a problem

Builds support for resulting solutions

Focuses the team on causes not symptoms

To discover the most probable causes for further analysis

To visualize possible relationships between causes for any problem current or future

To pinpoint conditions causing customer complaints, process errors or non-conforming products

To provide focus for discussion

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MethodsMaterials

Machinery Manpower

Maintenance

Problem/

Brainstorm to determine root causes and add those as small branches off major bones

Constructing Cause & Effect Diagrams

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Construction

constructed two ways:1.Paper and pen Usually more effective when working in a teamMay take multiple sheets of flip chart paperMany teams find it helpful to do the flip chart method first

because it lends itself to group dynamics. Everyone can see and participate easier.

2. Minitab softwareVery helpful when sharing diagram with an audience

outside of your team

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Example: Delayed Flight Departures

Equipment Personnel

Procedure

Material

Other

Aircraft late to gateLate arrivalGate occupied

Mechanical failureslate pushback tug

WeatherAir traffic

Late food serviceLate fuel

Late baggage to aircraft

Gate agents cannot process passengers quickly enoughToo few agentsAgents undertrained

Agents undermotivatedAgents arrive at gate late

Late cabin cleaners

late or unavailable cockpit crewsLate or unavailable cabin crews

poor announcement of departuresweight an balance sheet late

Delayed checkin procedureConfused seat selection

Passengers bypass checkin counterChecking oversize baggage

Issuance of boarding pass

Acceptance of late passengerscutoff too close to departure time

Desire to protect late passengersDesire to help company’s income

Poor gate locations

DelayedFlightDepartures

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Flowcharts This is a picture of a process that shows the sequence of steps performed.

It is also called a process map.

Used to document the detailed steps in a process

Often the first step in Process Re-Engineering

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Example: Process at Departure Gate

Scatter diagrams illustrate relationships between variables. Typically the variables represent possible causes and effects obtained from cause-and-effect diagrams.

Scatter Diagrams

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Checklist Simple data check-off sheet designed to identify type of quality problems at each work station; per shift, per machine, per operator

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Control Charts Important tool used in Statistical Process Control – Chapter 6 The UCL and LCL are calculated limits used to show when process is in or out of control

Control Chart Control charts are considered as the backbone of statistical process control and were first proposed by Walter Shewhart.

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Scatter Diagrams A graph that shows how two variables are related to one another

Data can be used in a regression analysis to establish equation for the relationship

Pareto Diagrams Pareto analysis is a technique for prioritizing types or sources of problems. It separates the “vital few” from the “trivial many” and provides help in selecting directions for improvement.

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Pareto AnalysisTechnique that displays the degree of importance for each element

Named after the 19th century Italian economist

Often called the 80-20 Rule

Principle is that quality problems are the result of only a few problems e.g. 80% of the problems caused by 20% of causes

Example of a Pareto Diagram

Histograms This is a graphical representation of the variation in a set of data. It shows the frequency or number of observations of a particular value or within a specified group.

It provides clues about the characteristics of the population from which a sample is taken.

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HistogramsA chart that shows the frequency distribution of observed values of a variable like service time

at a bank drive-up window

Displays whether the distribution is symmetrical (normal) or skewed

What is BenchmarkingWhat is BenchmarkingA method for identifying and importing best A method for identifying and importing best practices in order to improve performancepractices in order to improve performanceThe process of learning, adapting, and The process of learning, adapting, and measuring outstanding practices and processes measuring outstanding practices and processes from any organization to improve performancefrom any organization to improve performance

Why BenchmarkWhy BenchmarkIdentify opportunities to improve Identify opportunities to improve performanceperformanceLearn from others’ experiencesLearn from others’ experiencesSet realistic but ambitious targetsSet realistic but ambitious targetsUncover strengths in one’s own organizationUncover strengths in one’s own organizationBetter prioritize and allocate resourcesBetter prioritize and allocate resources

Citizens demand effective and responsive Citizens demand effective and responsive governmentgovernmentVoters resent waste of tax dollarsVoters resent waste of tax dollarsPeople ask for greater accountability of People ask for greater accountability of governmentgovernmentWeak economy forces government to provide Weak economy forces government to provide more services with less resourcemore services with less resource

Public Sector Public Sector BenchmarkingBenchmarking

Types of Benchmarking: Types of Benchmarking: 11Strategic BenchmarkingStrategic Benchmarking

How public, private, and nonprofit How public, private, and nonprofit organizations compare with each other. It organizations compare with each other. It moves across industries and cities to determine moves across industries and cities to determine what are the best strategic outcomes.what are the best strategic outcomes.

Types of Benchmarking: Types of Benchmarking: 22Performance BenchmarkingPerformance Benchmarking

How public, private, and nonprofit How public, private, and nonprofit organizations compare themselves with each organizations compare themselves with each other in terms of product and service. It other in terms of product and service. It focuses on elements of cost, technical quality, focuses on elements of cost, technical quality, service features, speed, reliability, and other service features, speed, reliability, and other performance comparisons.performance comparisons.

Types of Benchmarking: Types of Benchmarking: 33Process BenchmarkingProcess Benchmarking

How public, private, and nonprofit How public, private, and nonprofit organizations compare through the organizations compare through the identification of the most effective operating identification of the most effective operating practices from many organizations that perform practices from many organizations that perform similar work processes.similar work processes.

When not to When not to BenchmarkBenchmarkTarget is not critical to the core business Target is not critical to the core business functionsfunctionsCustomer’s requirement is not clearCustomer’s requirement is not clearKey stakeholders are not involvedKey stakeholders are not involvedInadequate resources to carry throughInadequate resources to carry throughNo plan for implementing findingsNo plan for implementing findingsFear of sharing information with other Fear of sharing information with other organizationsorganizations

Benchmarking ProcessBenchmarking ProcessPlanning

CollectingData

Analysis

ImprovingPractices

1. Planning1. PlanningDetermine the purpose and scope of the Determine the purpose and scope of the projectprojectSelect the process to be benchmarkedSelect the process to be benchmarkedChoose the teamChoose the teamDefine the scopeDefine the scopeDevelop a flow chart for the processDevelop a flow chart for the processEstablish process measuresEstablish process measuresIdentify benchmarking partnersIdentify benchmarking partners

2. Collecting Data2. Collecting DataConduct background research to gain Conduct background research to gain thorough understanding on the process and thorough understanding on the process and partnering organizationspartnering organizationsUse questionnaires to gather information Use questionnaires to gather information necessary for benchmarkingnecessary for benchmarkingConduct site visits if additional information is Conduct site visits if additional information is neededneededConduct interviews if more detail information Conduct interviews if more detail information is neededis needed

3. Analysis3. AnalysisAnalyze quantitative data of partnering Analyze quantitative data of partnering organizations and your organizationorganizations and your organizationAnalyze qualitative data of partnering Analyze qualitative data of partnering organizations and your organizationorganizations and your organizationDetermine the performance gapDetermine the performance gap

4. Improving Practices4. Improving PracticesReport findings and brief managementReport findings and brief managementDevelop an improvement implementation Develop an improvement implementation planplanImplement process improvementsImplement process improvementsMonitor performance measurements and Monitor performance measurements and track progresstrack progressRecalibrate the process as neededRecalibrate the process as needed

Failure Modes Effect Analysis(FMEA)

Benefits Allows us to identify areas of our process that most impact our customers

Helps us identify how our process is most likely to fail

Points to process failures that are most difficult to detect

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Application ExamplesManufacturing: A manager is responsible for moving a manufacturing operation to a new facility. He/she wants to be sure the move goes as smoothly as possible and that there are no surprises.Design: A design engineer wants to think of all the possible ways a product being designed could fail so that robustness can be built into the product.Software: A software engineer wants to think of possible problems a software product could fail when scaled up to large databases. This is a core issue for the Internet.

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What Is A Failure Mode? A Failure Mode is:

◦ The way in which the component, subassembly, product, input, or process could fail to perform its intended function◦ Failure modes may be the result of upstream operations

or may cause downstream operations to fail◦ Things that could go wrong

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What Can Go Wrong?

FMEA Why◦ Methodology that facilitates process improvement◦ Identifies and eliminates concerns early in the development of a process or

design◦ Improve internal and external customer satisfaction◦ Focuses on prevention◦ FMEA may be a customer requirement (likely contractual)◦ FMEA may be required by an applicable

Quality Management System Standard (possibly ISO)

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FMEA A structured approach to:

◦ Identifying the ways in which a product or process can fail◦ Estimating risk associated with specific causes◦ Prioritizing the actions that should be taken to reduce risk◦ Evaluating design validation plan (design FMEA) or current control plan

(process FMEA)

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When to Conduct an FMEA

Early in the process improvement investigationWhen new systems, products, and processes are being

designedWhen existing designs or processes are being changedWhen carry-over designs are used in new applicationsAfter system, product, or process functions are defined,

but before specific hardware is selected or released to manufacturing

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History of FMEA First used in the 1960’s in the Aerospace industry during the Apollo missions

In 1974, the Navy developed MIL-STD-1629 regarding the use of FMEA

In the late 1970’s, the automotive industry was driven by liability costs to use FMEA

Later, the automotive industry saw the advantages of using this tool to reduce risks related to poor quality

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Examples

The FMEA Form

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Identify failure modes and their effects

Identify causes of the failure modesand controls

Prioritize Determine and assess actions

A Closer Look

Types of FMEAs Design

◦ Analyzes product design before release to production, with a focus on product function

◦ Analyzes systems and subsystems in early concept and design stages

Process◦ Used to analyze manufacturing and assembly processes after they are

implemented

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Specialized Uses

FMEA: A Team Tool A team approach is necessary.

Team should be led by the Process Owner who is the responsible manufacturing engineer or technical person, or other similar individual familiar with FMEA.

The following should be considered for team members:– Design Engineers – Operators– Process Engineers – Reliability– Materials Suppliers – Suppliers– Customers

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Team Input Required

FMEA Procedure1. For each process input (start with high value inputs),

determine the ways in which the input can go wrong (failure mode)

2. For each failure mode, determine effectsSelect a severity level for each effect

3. Identify potential causes of each failure modeSelect an occurrence level for each cause

4. List current controls for each causeSelect a detection level for each cause

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Process Steps

FMEA Procedure (Cont.)5. Calculate the Risk Priority Number (RPN)

6. Develop recommended actions, assign responsible persons, and take actions

◦ Give priority to high RPNs◦ MUST look at severities rated a 10

7. Assign the predicted severity, occurrence, and detection levels and compare RPNs

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Process Steps

FMEA Inputs and Outputs

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FMEA

C&E MatrixProcess Map

Process HistoryProceduresKnowledgeExperience

List of actions to prevent causes or detect failure

modes

History of actions taken

Inputs Outputs

Information Flow

Severity, Occurrence, and Detection

Severity◦ Importance of the effect on customer requirements

Occurrence◦ Frequency with which a given cause occurs and

creates failure modes (obtain from past data if possible)

Detection◦ The ability of the current control scheme to detect

(then prevent) a given cause (may be difficult to estimate early in process operations).

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Analyzing Failure & Effects

Rating ScalesThere are a wide variety of scoring “anchors”, both quantitative or qualitativeTwo types of scales are 1-5 or 1-10The 1-5 scale makes it easier for the teams to decide on scoresThe 1-10 scale may allow for better precision in estimates and a wide variation in scores (most common)

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Assigning Rating

Weights

Rating Scales Severity

◦ 1 = Not Severe, 10 = Very Severe

Occurrence◦ 1 = Not Likely, 10 = Very Likely

Detection◦ 1 = Easy to Detect, 10 = Not easy to Detect

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Assigning Rating

Weights

Risk Priority Number (RPN)

RPN is the product of the severity, occurrence, and detection scores.

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Severity Occurrence Detection RPNRPNX X =

Calculating a Composite

Score