unit i introduction concepts of quality … · cs621 – software quality management unit - i mtech...

CS621 – Software Quality Management Unit - I

MTech CSE (PT, 2011-14) SRM, Ramapuram 1 hcr:innovationcse@gg

UNIT I INTRODUCTION Concepts of Quality Control, Quality Assurance, Quality Management - Total Quality Management; Cost of

Quality; QC tools - 7 QC Tools and Modern Tools; Other related topics - Business Process Re-engineering -

Zero Defect, Six Sigma, Quality Function Deployment, Benchmarking, Statistical process control

CONCEPTS OF QUALITY CONTROL Software Quality

Fitness for use – Boehm

Conformance to user requirement – Phil Crosby

Striving for excellence – Edward Deming

Achieving Excellent level of reliability, Maintainability, Portability – Watt Humphrey

Low defect level – Tom McCabe

Quality is people – Allan Gillies

Why Software Quality is Important

one of major customer’s demand

competitive issue

important for survival in global market

makes the manufacturer to global reach

cost effective, increases the profit

critical for survival and success

a hall mark for world class business

Quality criteria are not independent

View of quality differs from one to other

User satisfaction = Complaint product + good quality + Delivery within budget and schedule

Why Software Quality is Difficult

Software has no physical existence

Lack of knowledge of client needs at the start

Change of client needs over time

Rapid rate of change in both H/W and S/W

High expectations of customer with respect to adaptability

View Of Quality

Transcendent view

o It relates quality to innate excellence

Product based view

o Quality is free of cost – Crosby. 80% development cost for maintenance

User based view

o Fitness for purpose, needs, use

Manufacturing view

o Conformance to requirements – CASE, TQM, Zero defect approach

Value base view

o Affordable price for product by customer

Changing View of Quality

Past Present

Responsibility of to blue-collar workers and employees

working on the product

Everyone’s Responsibility including over head staff

Defects were hidden from customer and management Defects are brought to surface of corrective action and

highlighted

Quality problem leads to fault justification Quality problem leads to co-operative solutions



Quality is internally focused Quality is customer focused

Quality Check occurred during the project execution Quality check occurs at project initiation and continues

till maintenance

Increasing quality led to increasing project cost Improving quality saves money and increases money

Correction to quality problems was accompanied with

minimum documention

Documentation are essential so that the mistakes are

not repeated

How to Achieve a Quality Software

Software quality control – Corrective action

Software Quality Assurance – Preventive action

Total Quality management – Managing the entire organisation to achieve excellence

Eight dimensions of quality (PFR-CD-SAP)

Performance

o Primary operating characteristics of a product

Features

o Bells and whistles of a product

Reliability

o Reflects the probability of a product failing within a specified period of time

o MTFF / MTBF

Conformance

o Degree to which product design and operating characteristics match preestablished standards

Durability

o Measure of product life

Serviceability

o Speed / competency and efficiency of repair

o MTTR

Aesthetics

o Subjective

o Looks, feels, sounds, tastes ans smells

o Individual preference

Perceived quality

o Indirect method of comparing of brands

SOFTWARE QUALITY CONTROL Corrective Approach

Operational techniques and activities used to fulfil the requirements for quality

Ensuring that procedures and standards are being followed

Key Concept of Software Quality Control

All work product should be defined

There exists manageable specifications

Output of each process should be comparable

There should be feedback loop

It should minimize the variation control between predicted project with actual project

Two Approaches to Software Quality Control

Quality Review

o Design or program inspection - To detect detailed errors occurred during the software life cycle. Check

list of possible error drives the review

o Progress review – Overall progress of project both process and product

o Quality review – to find the mismatch of requirements, to meet the standards

Automated software assessment and measurement

o Seven QC tools

o Modern QC tools



o Structured System and Design Method (SSADM)

o Information Engineering Methodology(IEM)

o CASE Tools

QUALITY ASSURANCE Software Quality Assurance

Preventive Approach

It is the planned and systematic activities implemented within the quality systems

Why Software Quality Assurance is important

If team size grows and manager involves in other duties, then the monitoring of work is not done

To motivate the people to monitor each other

To ensure the inadequacies in the project or process or product

To ensure full compliance with the established standards

Responsibilities of SQA

Review the all developments and quality plans for completeness

Review all test plans for adherence to standards

Review a significant sample of all test results to determine adherence to plans

Periodically audit SCM performance to determine adherence to standards

Participate as inspection moderators in design and code inspections

Benefits of Quality assurance

An appropriate development methodology is in place

The projects use standards and procedures in the work

Independent reviews and audits are conducted

Documentation is produced to support maintenance and enhancement

The documentation is produced during the development

Mechanisms are in place and used to control changes

Testing emphasizes all the high risk product areas

Deviation from standards and procedures are exposed as soon as possible

The project is auditable by external professionals

The SQA plan and development plan are compatible

Eight Steps to launch a SQA program

Initiate SQA Program – Management commitment, Goal documentation, Identify the resp. and team leader

Identify the SQA issues

Write a SQA program – Identify the standards and procedure, Define SQA audit and control activities

Establish Standards

Establish SQA functions

Conduct training and promote the SQA program

Implement the SQA plan – SQA activity is assigned to SQA personnel

Evaluate the SQA program – periodical audit, corrective action and preventive action

Various Standards to Achieve SQA

ISO 9000, 9001

SPICE - Software Process Improvement and Capability dEtermination

CMM

CMMI – Capability Maturity Model Integration

Software Quality Control Software Quality Assurance

Corrective (reactive) Preventive (proactive)

Product Processes

Confidence to producer Confidence to Customers



Line Function Staff Function

Find Defects Prevent Defects

Walkthrough Defining processes

Testing Quality Audit

Inspection Selection of tools

Checkpoint Review Training

TOTAL QUALITY MANAGEMENT Total - Made up of the whole

Quality - degree of excellence a product or service provides

Management - Act, art or manner of planning, controlling, directing

Therefore, TQM is the art of managing the whole to achieve excellence

Goal Of TQM

“Do the right things right the first time, every time.”

TQM is all managers leading and facilitating all contributors in everyone’s two main objectives:

Total client satisfaction through quality products and services;

Continuous improvements to processes systems, people, suppliers, partners, products, and services.

Elements of TQM

Top management commitment and involvement

Customer involvement

Design products for quality

Design production processes for quality

Control production processes for quality

Develop supplier partnerships

Customer service, distribution and installation

Building teams of empowered employees

Benchmarking and continuous improvement

Basic Tenets (Beliefs) of TQM

The customer makes the ultimate determination of quality.

Top Management must provide leadership and support for all quality initiatives.

Preventing variability is the key to producing high quality.



Quality goals are a moving target, thereby requiring a commitment toward continuous improvement.

Improving quality requires the establishment of effective metrics. We must speak with data and facts not

just opinions

Traditional Approach Continuous Improvement

Market-share focus

Individuals

Focus on ‘who” and “why”

Short-term focus

Status quo focus

Product focus

Innovation

Fire fighting

Customer focus

Cross-functional teams

Focus on “what” and “how”

Long-term focus

Continuous improvement

Process improvement focus

Incremental improvements

Problem solving

COST OF QUALITY (COQ) Cost of quality is the sum of costs incurred by an organization in preventing poor quality

Quality costs are the costs associated with preventing, finding, and correcting defective work.

Quality is cost effective.

It enables the management to reduce the defect correction cost

Types of Quality Costs (PAF Model)

Prevention cost

o Quality planning, formal technical review, testing, training

Appraisal cost

o Equipment calibration, inter-process inspection, in-process inspection

Failure cost

o incurred in correcting defects found by appraisal.

o Internal failure cost (rework and repair)

o External failure cost (defects found after shipment)

Prevention Cost

Staff Training

Requirement analysis

Early prototyping

Fault tolerant design

Defensive programming

Usability analysis

Clear specification

Accurate internal doc.

Appraisal cost

Design Review

Code inspection

Glass box testing

White box testing

Training testers

Beta testing

Test automation

Usability testing

Internal Failure

Bug fixes

Regression testing

Wasted in-house user time

Wasted writer time

Wasted marketer time

Wasted advertisement

Direct cost of late shipment

External Failure

Warranty cost

Liability cost

Penalties

Preparation support answer book

Investigation of customer support

PR work, Investigation of customer complaint



7 QC TOOLS – CFC-HPCS

Why Seven QC Tools

Improve Quality

Decrease Costs

Improve Productivity

Decrease Price

Increase Market

Stay in Business

Provide More Jobs

Return on Investment

Six Problem solving Steps

Identify - recognize the symptoms

Define - Agree on the problem and set boundaries

Investigate - Collect data

Analyze - Use quality tools to aid

Solve - Develop the solution and implement

Confirm - Follow up to ensure that the solution is effective

7 QC Tools

Cause and Effect Diagrams

Flow Charts

Check sheets

Histograms

Pareto Charts

Control Charts

Scatter Diagrams

Cause and Effect Diagrams

Also called as Fish bone / Ishikawa diagram

Purpose

o Graphical representation of the trail leading to the root cause of a problem

How is it done?

o Decide which quality characteristic, outcome or effect you want to examine (may use Pareto chart)

o Backbone –draw straight line

o Ribs – categories

o Medium size bones –secondary causes

o Small bones – root causes

Benefits:

o Breaks problems down into bite-size pieces to find

root cause

o Fosters team work

o Common understanding of factors causing the

problem

o Road map to verify picture of the process

o Follows brainstorming relationship

Flow Charts

Purpose:

o Visual illustration of the sequence of

operations required to complete a task

o Schematic drawing of the process to

measure or improve.

o Starting point for process improvement

o Potential weakness in the process are

made visual.

o Picture of process as it should be.

Benefits:

o Identify process improvements

o Understand the process

o Shows duplicated effort and other non-

value-added steps



o Clarify working relationships between people and organizations

o Target specific steps in the process for improvement.

o Show what actually happens at each step in the process

o Show what happens when non-standard events occur

o Graphically display processes to identify redundancies and other wasted effort

How is it done?

o Write the process step inside each symbol

o Connect the Symbols with arrows showing the direction of flow

Check sheets

Purpose:

o Tool for collecting and organizing measured or counted data

o Data collected can be used as input data for other quality tools

Benefits:

o Collect data in a systematic and organized manner

o To determine source of problem

o To facilitate classification of data (stratification)

Histograms

Purpose:

o To determine the spread or variation of a set of data points in a graphical form

How is it done?:

o Collect data, 50-100 data point

o Determine the range of the data

o Calculate the size of the class interval

o Divide data points into classes Determine the

class boundary

o Count # of data points in each class

o Draw the histogram

Benefits:

o Allows you to understand at a glance the

variation that exists in a process

o The shape of the histogram will show process

behavior

o Often, it will tell you to dig deeper for otherwise

unseen causes of variation.

o The shape and size of the dispersion will help

identify otherwise hidden sources of variation

o Used to determine the capability of a process

o Starting point for the improvement process

Pareto Charts

Purpose:

o Prioritize problems.

How is it done?

o Create a preliminary list of problem

classifications.

o Tally the occurrences in each problem

classification.

o Arrange each classification in order

from highest to lowest

o Construct the bar chart

Benefits:

o Pareto analysis helps graphically display

results so the significant few problems

emerge from the general background

o It tells you what to work on first



Control Charts

Purpose:

o The primary purpose of a control chart is to predict expected product outcome.

Benefits:

o Predict process out of control and out of specification limits

o Distinguish between specific, identifiable causes of variation

o Can be used for statistical process control

How is it done?

o The data must have a normal distribution (bell curve).

o Have 20 or more data points. Fifteen is the absolute minimum.

o List the data points in time order. Determine the range between each of the consecutive data points.

o Find the mean or average of the data point values.

o Calculate the control limits (three standard deviations)

o Set up the scales for your control chart.

o Draw a solid line representing the data mean.

o Draw the upper and lower control limits.

o Plot the data points in time sequence.

Scatter Diagrams

Purpose:

o To identify the correlations that might exist between a quality

characteristic and a factor that might be driving it

o A scatter diagram shows the correlation between two variables

in a process.

o These variables could be a Critical To Quality (CTQ)

characteristic and a factor affecting it two factors affecting a

CTQ or two related quality characteristics.

o Dots representing data points are scattered on the diagram.

o The extent to which the dots cluster together in a line across the

diagram shows the strength with which the two factors are

related.

How is it done?:

o Decide which paired factors you want to examine. Both factors must

be measurable on some incremental linear scale.

o Collect 30 to 100 paired data points.

o Find the highest and lowest value for both variables.

o Draw the vertical (y) and horizontal (x) axes of a graph.

o Plot the data

o Title the diagram

o The shape that the cluster of dots takes will tell you something about the relationship between the two

variables that you tested.



MODERN TOOLS – A-RTM-APM Affinity Diagrams

Relations Diagrams

Tree Diagrams

Matrix Diagrams

Arrow Diagrams

Process Decision Program Charts

Matrix Data Analysis

History of the New Seven Q.C. Tools

Developed to organize verbal data diagrammatically.

Basic 7 tools effective for data analysis, process control, and quality improvement (numerical data)

Used together increases TQM effectiveness

Relation Between New Seven Q.C. Tools and Basic Seven Tools

Benefits of Incorporating New Seven Q.C. Tools

Enhanced Capabilities

o Organize verbal data

o Generate ideas

o Improve planning

o Eliminate errors and omissions

o Explain problems intelligibly

o Secure full cooperation

o Persuade powerfully

Enhanced Keys to Organizational Reform

o Assess situations from various angles

o Clarify the desired situation

o Prioritize tasks effectively

o Proceed systematically

o Anticipate future events

o Change proactively

o Get things right the first time

Five Objectives of Organizational Reform which will establish a Culture that

o Identifies problems

o Gives importance to planning

o Stresses the importance of the process

o Prioritizes tasks

o Encourages everyone to think systematically



Affinity Diagrams

For Pinpointing the Problem in a Chaotic Situation and Generating Solution Strategies

Gathers large amounts of intertwined verbal data (ideas, opinions, issues)

Organizes the data into groups based on natural relationship

Makes it feasible for further analysis and to find a solution to the problem

Advantages

Facilitates breakthrough thinking and stimulate fresh ideas

Permits the problem to be pinned down accurately

Ensures everyone clearly recognizes the problem

Incorporates opinions of entire group

Fosters team spirit

Raises everyone’s level of awareness

Spurs to the group into action

Method: Group Method Approach

Select a topic

Collect verbal data by brainstorming

Discuss info collected until everyone understands it thoroughly

Write each item on separate data card

Spread out all cards on table

Move data cards into groups of similar themes (natural affinity for each other)

Combine statements on data cards to new Affinity statement

Make new card with Affinity statement

Continue to combine until less than 5 groups

Lay the groups outs, keeping the affinity clusters together

Next, complete the diagram

Relations Diagrams

For Finding Solutions Strategies by Clarifying Relationships with Complex Interrelated Causes

Resolves tangled issues by unraveling the logical connection

Allows for “Multi-directional” thinking rather than linear

Also known as Interrelationship diagrams

Advantages

Useful at planning stage for obtaining perspective on overall situation

Facilitates consensus among team

Assists to develop and change people’s thinking

Enables priorities to be identified accurately

Makes the problem recognizable by clarifying the relationships among causes

Group Method Approach

Express the problem in form of “Why isn’t something happening?”

Each member lists 5 causes affecting problem

Write each item on a card

Discuss info collected until everyone understands it thoroughly

Move cards into similar groups

Asking why, explore the cause-effect relationships, and divide the cards into primary, secondary and tertiary

causes

Connect all cards by these relationships

Further discuss until all possible causes have been identified

Review whole diagram looking for relationships among causes

Connect all related groups




Tree Diagrams

For Systematically Pursuing the Best Strategies for Attaining an Objective

Develops a succession of strategies for achieving objectives

Reveals methods to achieve the results

Also known as Systematic diagrams or

Dendrograms

Advantages

Systematic and logical approach is less likely

that items are omitted

Facilitates agreement among team

Are extremely convincing with strategies

Method

Write Relations Diagram topic (Objective card)

Identify constraints on how objective can be

achieved

Discuss means of achieving objective (primary means, first level strategy)

Take each primary mean, write ob-jective for achieving it (secondary means)

Continue to expand to the fourth level

Review each system of means in both directions (from objective to means and means to objective)

Add more cards if needed

Connect all levels


Matrix Diagrams

For Clarifying Problems by “Thinking

Multidimensionally”

Consists of a two-dimensional array to determine

location and nature of problem

Discovers key ideas by relationships represented

by the cells in matrix

Advantages

Enable data on ideas based on extensive experience

Clarifies relationships among different elements

Makes overall structure of problem immediately obvious

Combined from two to four types of diagrams, location of problem is clearer

5 types: L-shaped, T-shaped, Y-shaped, X-shaped, and C-shaped

Method

Write final-level means from Tree diagram forming vertical axis



Write in Evaluation categories (efficacy, practicability, and rank) on horizontal axis

Examine final-level means to identify whom will implement them

Write names along horizontal axis

Label group of columns as “Responsibilities”

Label right-hand end of horizontal axis as “Remarks”

Examine each cell and insert the appropriate symbol

o

o

Determine score for each combination of symbols, record in rank column

Examine cells under Responsibility Columns, insert double-circle for Principal and single-circle for

Subsidiary

Fill out remarks column and record meanings of symbol


Arrow Diagrams

For Working Out Optimal Schedules and

Controlling Them Effectively

Shows relationships among tasks needed

to implement a plan

Network technique using nodes for events

and arrows for activities

Used in PERT (Program Evaluation and

Review Technique) and CPM (Critical

Path Method)

Advantages

Allows overall task to viewed and potential snags to be identified before work starts

Leads to discovery of possible improvements

Makes it easy to monitor progress of work

Deals promptly with changes to plan

Improves communication among team

Promotes understanding and agreement among group

Method

From strategies on Tree diagram, select one (Objective of Arrow Diagram)

Identify constraints to Objective

List all activities necessary to achieving Objective

Write all essential activities on separate cards

Organize cards in sequential order of activities

Remove any duplicate activities

Review order of activities, find sequence with greatest amount of activities

Arrange parallel activities

Examine path, number nodes in sequence from left to right

Record names and other necessary information


Process Decision Program Charts

For Producing the Desired Result from Many

Possible Outcomes

Used to plan various contingencies

Used for getting activities back on track

Steers events in required direction if

unanticipated problems occur

Finds feasible counter measures to overcome

problems



Advantages

Facilitates forecasting

Uses past to anticipate contingencies

Enables problems to pinpointed

Illustrates how events will be directed to successful conclusion

Enables those involved to understand decision-makers intentions

Fosters cooperation and communication in group

Easily modified and easily understood

Method

Select a highly effective, but difficult strategy from the Tree diagram

Decide on a goal (most desirable outcome)

Identify existing situation (Starting point)

Identify constraints of objective

List activities to reach goal and potential problems with each activity

Review list. Add extra activities or problems not thought of previously

Prepare contingency plan for each step and review what action is needed if step is not achieved

Examine carefully to check for inconsistencies and all important factors are included

Examine to make sure all contingency plans are adequate


Matrix Data Analysis

Principal Component Analysis

Technique quantifies and arranges data presented in Matrix

Based solely on numerical data

Finds indicators that differentiate and attempt to clarify large amount of information

Advantages

Can be used in various fields (market surveys, new product planning, process analysis)

Can be when used when Matrix diagram does not give sufficient information

Useful as Prioritization Grid

Method

Determine your goal, your alternatives, and criteria for decision

Place selection in order of importance

Apply percentage weight to each option (all weights should add up to 1)

Sum individual ratings to establish overall ranking (Divide by number of options for average ranking)

Rank order each option with respect to criterion (Average the rankings and apply a completed ranking)

Multiply weight by associated rank in Matrix (in example, 4 is best, 1 is worst)

Result is Importance Score

Add up Importance Scores for each option

Rank order the alternatives according to importance

See completed the diagram



BUSINESS PROCESS RE-ENGINEERING Reengineering is the fundamental rethinking and redesign of business processes to achieve dramatic

improvements in critical, contemporary measures of performance, such as cost, quality, service and speed

Process

A specific ordering of work activities across time and space, with a beginning, an end, and clearly identified

inputs and outputs: a structure for action

Business Process

A group of logically related tasks that use the firm's resources to provide customer-oriented results in

support of the organization's objectives.

A designed succession of actions to the accomplish of some result in a business.

Why Reengineer?

Customers – Demanding, Sophistication, Changing Needs

Competition – Local, Global

Change – Technology,

Customer Preferences

BPR seeks improvements of

Cost

Quality

Service

Speed

Five Step approach to BPR

Step 1: Develop the business vision and process objectives

o Cost reduction

o Time reduction

o Output quality improvement

o Quality of Work Life / Learning / Empowerment

Step 2:Identify the processes to be redesigned

o High impact approach

Most important processes or those that conflict most with the business vision

o Exhaustive approach

Identify all processes within the organization and prioritize them in order of redesign urgency

Step 3: Understand and measure the existing processes

o To avoid repeating of old mistakes

o To provide a baseline for future improvements

Step 4: Identify IT levers

o Awareness of IT capabilities can / should influence process design

Step 5: Design and build a prototype of the new process

o Actual design should not to be viewed as the end of the BPR process

o Should be viewed as a prototype with successive iterations

Advantages / Benefits of BPR

Re-engineering integrates various tasks and activities into one

The steps in process are performed in natural order, which is not necessarily linear

Work is performed where it makes most sense

Non-value adding activities are eliminated

There is no place for the command and control type of management style

Processes are understood from the perspective of the customers

Full and open communication becomes important

It promotes rethinking the nature and purpose of work

It restores respect for the individual

Work assumes multi-dimensional perspectives



Corporate and individual values change from being protective to productive

Smart work rather than hard work becomes the norm

Organizational structure becomes flat and functional silos and functional stovepipes disappear

Technology as an enabler becomes an important agent of business transformation and success

The organizations attention is focused on where to compete rather than how to compete

It promotes provocative culture – questioning, everything an organization does and seeking innovative ways

of doing work

It aligns core processes to business strategy

It promotes an organization’s capability to adapt

Process Simplification BPR

Incremental Change

Process-Led

Assume Attitudes & Behaviours

Management-Led

Various Simultaneous Projects

Radical Transformation

Vision-Led

Change Attitudes & Behaviours

Director-Led

Limited Number of Initiatives

Continuous Improvement BPR

Incremental Change

People Focus

Low Investment

Improve Existing

Work Unit Driven

Radical Transformation

People & Technology Focus

High Investment

Rebuild

Champion Driven

Common Problems with BPR / Why Re-engineering fails

Process under review too big or too small

Reliance on existing process too strong

The Costs of the Change Seem Too Large

BPR Isolated Activity not Aligned to the Business Objectives

Allocation of Resources

Poor Timing and Planning

Keeping the Team and Organization on Target

ZERO DEFECT Refer to 5

th Unit for more details

Practice of developing software that is maintained in the highest quality state throughout the entire

development process

Maintain your product in what you believe to be a defect-free state throughout the development process

By focusing on product quality throughout the development lifecycle, you will actually complete products

faster than if you didn't pay attention to quality until the end of the project



SIX SIGMA Sigma is a measure of “goodness: the capability of a process to produce perfect work.

Six Sigma’s goal is the near elimination of defects from any process, product, or service.

A “defect” is any mistake that results in customer dissatisfaction.

Sigma indicates how often defects are likely to occur.

The higher the sigma level, the lower the defect rate.

The lower the defect rate, the higher the quality.

Why Sigma as a Quality Measure

Sigma allows comparison of products and services of varying complexity on an apples to apples basis.

Also, it provides a common basis for benchmarking (competitors and non-competitors).

The higher the sigma level, the better your operation is performing.

Sigma measures how well you’re doing in getting to zero defects.

Six Step to Six Sigma

Step1: Identify the product you create or the service you provide.

Step2: Identify the Customer(s) for your product or service and determine what they consider important.

Step3: Identify your needs (to provide product/service so that it satisfies the Customer).

Step4: Define the process for doing the work.

Step5: Mistake-proof the process and eliminate wasted effort.

Step6: Ensure continuous improvement by measuring, analyzing, and controlling the improved process.

Six Sigma Process Capability

SIGMA DPMO COPQ CAPABILITY

6 sigma 3.4 < 10% of sales World Class

5 230 10 – 15%

4 6200 15 – 20% Industry average

3 67000 20 – 30%

2 310000 30 – 40% Noncompetitive

1 700000

Normal distribution Curve



Example: Six Sigma Project: Engineering Changes

Define

o Large number of changes from client after approving engineering design. Schedule slipping.

Measure

o Number of changes, time involved in changes, compliance to critical path schedule.

Analyze

o No clear authority on client team to establish scope, any of client team could make changes, verbal

communication of changes, conflicting changes by client team members. Language issues between

client and engineers.

Improve

o Regular engineering/client meetings where topics include: scope for each section and desired

objective, known limitations defined, unclear requirements were questioned and options discussed.

Written plan signed by client representative and engineering lead. Change requests in writing and

signed by client representative. Changes decrease by factor of 4.7 and schedule met.

Control

o Change requests all in writing. Shared approach with other disciplines on project.

What are the Challenges of Six Sigma?

The perception of “Sick Sigma”

Culture change

Understanding the DFSS (Design For Six Sigma)

It is not a quick fix nor a recipe.

Consultants can’t make it happen

Implementation tends to be uneven and lapses occur frequently.

Not everything has to be Six Sigma; this was our downfall on reengineering efforts!

Lack of discipline and accountability

Training – especially management level

Takes careful preparation and a commitment to the foundational change efforts required.

Statistical analysis is not generally part of the engineering discipline in most IT shops

Reliability of data from the field.

People must not fear giving “bad news”.

Design is critical and yet many IT organizations continue to go straight from poor requirements into coding

without the benefits of even one design review

QUALITY FUNCTION DEPLOYMENT The basic idea of QFD is to transform the customer requirement into design requirement

House of Quality



How to Build a house of quality

Gather customer attributes (in the words of the customer)

Group attributes logically

Assess relative importance of the attributes

Assess competitive performance on the attributes

Describe product in terms of engineering characteristics

Detail influence of engineering characteristics on customer attributes

Detail interaction between engineering characteristics

How to Use a house of quality

Prioritize on attributes that we do poorly on, or where we might increase our lead

Determine what engineering characteristics strongly influence the desired attribute

Check for adverse interactions and weigh tradeoffs

Set target levels (not ranges)

Link to lower level houses

o Parts characteristics

o Key process operations

o Production requirements

Quality Function Deployment

Six steps for building a house of quality

Step 1. The primary customer requirements are normally expanded into secondary and tertiary

requirements using AND/OR tree.

Step 2. The design requirements must be related to the customer requirements and should be selectively

deployed throughout the manufacturing, assembly, and service process to manifest themselves in the final

product performance and customer acceptance.

Step 3. Developing a matrix describing the customer requirements and the design requirements is

accomplished

Step 4. Market evaluation which covers the customer-expressed importance ratings, requirements, and

competitive products is performed.

Step 5. The target for each of the design requirement is defined.

Step 6. Selection of the best solution should be deployed

Benefits of QFD

Product objectives based on customer requirements are not misinterpreted at the subsequent stages

Particular marketing strategies or sales points do not become lost or blurred during the translation process

from marketing through planning to execution

Important production control points are not overlooked - everything necessary to achieve the desired

outcome is understood

Efficiency is improved as the misinterpretation of design objectives, marketing perception, and critical

control points, and the need for changes is minimized



Problem with QFD

Matrix is too large

o Prioritize on important attributes

o Analyzes independent subsystems independently

Customer priorities not clear

o Consider segmenting market

Customers’ stated preferences and actions differ

o Use revealed preference techniques if you suspect a problem

QFD is messy

o Not QFD, but rather the interaction between diverse groups is cause

o Stick with it, the results are worthwhile

BENCHMARKING The practice of establishing internal standards of performance by looking to how world-class companies run

their businesses

Benchmarking is about identifying and measuring best practice processes that work elsewhere and then

emulating them.

The aim is to reduce duplication by learning from others who have already found the solution.

It is about:

o Understanding your weaknesses

o Comparison with your peers

What other type of benchmarking activities are useful?

Monitoring Content Quality and ‘Freshness’

New developments and technologies - scripts, other markup languages, personalisation

Stress and security

Search engine used on site and 404 pages

Server numbers

Visibility on search engines

Usability e.g. by evaluating user feedback

Performance checkers and Independent testing services

Malcolm Baldrige Award

The Malcolm Baldrige National Quality Award originated in 1987 to recognize companies that have

achieved a level of world-class competition through quality management.

Given by the President of the United States to U.S. businesses.

Three awards each year in different categories:

o Manufacturing, Service, Small business, Education and health care



STATISTICAL PROCESS CONTROL The application of statistical techniques to the control and improvement of processes.

Tool to supplement, not replace the existing knowledge your people have of your process

Basic of SPC

Statistical Process Control (SPC)

o monitoring production process to detect and prevent poor quality

Sample

o subset of items produced to use for inspection

Control Charts

o process is within statistical control limits

Benefits of SPC

increased profits

increased productivity

increased employee involvement in the process

increased morale

Who is Responsible for SPC

Everyone in the plant – Management, Production, Engineering and design, sales

Managing Variation over time

Statistical Process Control often takes the form of a continuous Hypothesis testing.

The idea is to detect, as quickly as possible, a significant departure from the norm.

A significant change is often attributed to what is known as an assignable cause.

An assignable cause is something that can be discovered and corrected at the machine level.

Variability

Random

o common causes

o inherent in a process

o can be eliminated only through improvements in the system

Non-Random

o special causes

o due to identifiable factors

o can be modified through operator or management action

What are the sources of variation in a process?

Machine variation

Raw Material variation

Different methods used

Measurement variation

Operator variation

Environmental factors

Assignable Cause

An "Assignable Cause" relates to relatively strong changes, outside the random pattern of the process.

It is "Assignable", i.e. it can be discovered and corrected at the machine level.

Although the detection of an assignable cause can be automated, its identification and correction often

requires intimate understanding of the manufacturing process.

For example

o Symptom: significant yield drop.

o Assignable Cause: leaky etcher load lock door seal.

o Symptom: increased e-test rejections

o Assignable Cause: probe card worn out.



10 Steps of Implementing SPC

Analyze the process

Decrease obvious variability

Gauge capability study

Sampling plan

Implement CONTROL CHARTS

Put the operator in charge

Process capability study

Improve the process

Reduce sampling

Return to step 1

Control Chart

A graph that establishes control limits of a process

Control limits - upper and lower bands of a control chart

Quality Measure

Attribute

o a product characteristic that can be evaluated with a discrete response : good – bad; yes - no

Variable

o a product characteristic that is continuous and can be measured

o weight – length

Types of charts

Attributes

o p-chart

o c-chart

Variables

o range (R-chart)

o mean (x bar – chart)

Process Control Chart

Credits

Thanks to the SRM MTech staff, who have provided us the PPTs, which were very helpful in creating this

Comments & Feedback

Thanks to my family members who supported me while I spent hours and hours to prepare this.

Your feedback is welcome at [email protected]

unit i introduction concepts of quality … · cs621 – software quality management unit - i mtech...

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