1 q uality f unction d eployment david menks anwar ahmed kaijun fu found at:...
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1
Quality Function
Deployment
David MenksAnwar Ahmed
Kaijun Fu
Found at: http://sern.ucalgary.ca/~kjfu/courses/SENG613/teamwork.htmlFound at: http://sern.ucalgary.ca/~kjfu/courses/SENG613/teamwork.html
Acknowledging:
Nov 23, 2000 SENG 613 QFD 2
Good overview can be found at:http://pages.cpsc.ucalgary.ca/~johnsonk/SENG/SENG613/Project/report.htm
Downloadable tool:
www.iti-oh.com
SQFD paper: (see other slides)
Other Sources on QFD/SQFD
Nov 23, 2000 SENG 613 QFD 3
Table of Contents Overview QFD: Step by Step Exercise Comparison of Different RE Techniques Application of QFD on Software
Engineering QFD software list Discussion
Nov 23, 2000 SENG 613 QFD 4
Overview of QFD The History of QFD.
What is QFD? Why use QFD? Characteristics of QFD?
Nov 23, 2000 SENG 613 QFD 5
History of QFD 1960’s, Yoji Akao conceptualized
QFD. Statistical Quality Control, SQC, was
the central quality control activity after WWII.
SQC became Total Quality Control, TQC.
QFD was derived from TQC.
Nov 23, 2000 SENG 613 QFD 6
First Application of QFD 1966, Bridgestone Tire Corp first used a
process assurance table. 1972, the process assurance table was
retooled by Akao to include QFD process. 1972, Kobe Shipyards (of Mitsubishi Heavy
Industry) began a QFD Oil Tanker project. 1978, Kobe Shipyards published their
quality chart for the tanker.
Nov 23, 2000 SENG 613 QFD 7
QFD Takes Hold The first paper on QFD was published
in 1972. In 1978, the first book on QFD was
published in Japanese. In 1983, the first English QFD article
was published in North America. By the late 1970’s most of the
Japanese manufacturing industry were using QFD.
Nov 23, 2000 SENG 613 QFD 8
QFD in North America QFD spread rapidly in North America during
the 1980’s The Automobile industry and Manufacturing
began heavy use of QFD at this time. QFD symposiums (North American, Japanese,
European, International) were set up to explore research relating to QFD techniques.
The QFD institute was formed in 1994.
Nov 23, 2000 SENG 613 QFD 9
QFD in Software Engineering
The QFD Research Group was seeking research relating to QFD in Software Engineering since 1987.
A new style of QFD, Software QFD (SQFD), has emerged.
DEC, AT&T, HP, IBM and Texas Instruments have all published information relating to SQFD (Haag, 1996).
Nov 23, 2000 SENG 613 QFD 10
Additional Techniques There are many techniques which are a
style of QFD or are used to enhance QFD.
These include: TRIZ, conjoint analysis, the seven product planning tools, Taguchi methods, Kano model, SQFD, DQFD, Gemba, Kaizen, Comprehensive QFD, QFD (N), QFD (B).
Nov 23, 2000 SENG 613 QFD 11
Overview of QFD The History of QFD.
What is QFD?
Why use QFD? Characteristics of QFD?
Nov 23, 2000 SENG 613 QFD 12
What is QFD? Quality Function Deployment, QFD, is a quality
technique which evaluates the ideas of key stakeholders to produce a product which better addresses the customers needs.
Customer requirements are gathered into a visual document which is evaluated and remodeled during construction so the important requirements stand out as the end result.
Nov 23, 2000 SENG 613 QFD 13
The QFD Paradigm QFD provides the opportunity to make sure
you have a good product before you try to design and implement it.
It is about planning and problem prevention, not problem solving (Eureka, 1988).
QFD provides a systematic approach to identify which requirements are a priority for whom, when to implement them, and why.
Nov 23, 2000 SENG 613 QFD 14
High-Level QFD Requirements are initially elicited using other
RE techniques (interviewing, brain-storming, focus-groups, etc).
QFD involves the refinement of requirements using matrices and charts based on group decided priorities.
There are 4 Phases of QFD. Each Phase requires internal iteration before proceeding to the next. Once at a Phase you do not go back.
Nov 23, 2000 SENG 613 QFD 15
What Does QFD Require? QFD requires time, effort, and patience. QFD requires access to stakeholder groups. The benefits of QFD are not realized
immediately. Usually not until later in the project or the next project.
QFD requires full management support. Priorities for the QFD process cannot change if benefits are to be realized.
Nov 23, 2000 SENG 613 QFD 16
Overview of QFD The History of QFD. What is QFD?
Why use QFD?
Characteristics of QFD?
Nov 23, 2000 SENG 613 QFD 17
Why use QFD? The QFD process leads participants
to a common understanding of project direction and goals.
QFD forces organizations to interact across their functional boundaries (Hales, 1995).
QFD reduces design changes (Mazur, 2000).
Nov 23, 2000 SENG 613 QFD 18
Nov 23, 2000 SENG 613 QFD 19
QFD Artifacts Prioritized list of customers and
competitors. Prioritized list of customer requirements. Prioritized list of how to satisfy the
requirements. A list of design tradeoffs and an indication
of how to compromise and weigh them. A realistic set of target values to ensure
satisfaction.
Nov 23, 2000 SENG 613 QFD 20
What about Cost? Cost reduction is not mentioned as
a ‘Why to use QFD’. Initial costs will be as high or a
little higher compared with traditional techniques.
You are seeking long term savings in that product or the products that follow.
Nov 23, 2000 SENG 613 QFD 21
Overview of QFD The History of QFD. What is QFD? Why use QFD?
Characteristics of QFD?
Nov 23, 2000 SENG 613 QFD 22
Characteristics of QFD 4 Main Phases to QFD
Product Planning including the ‘House of Quality’ (Requirements Engineering Life Cycle)
Product Design (Design Life Cycle) Process Planning (Implementation Life
Cycle) Process Control (Testing Life Cycle)
Nov 23, 2000 SENG 613 QFD 23
QFD Phase 1 Phase 1 is where most of the
information is gathered. Getting good data is critical. Any
mistakes in requirements here will be magnified later.
Software Engineers should spend most of our time in this Phase.
Nov 23, 2000 SENG 613 QFD 24
The House of Quality (HoQ)
Is a set of matrices which contains the requirements (What’s) and the detailed information to achieve those requirements (How’s, How Much’s).
Stakeholder groups fill in the matrices based on their priorities and goals.
A key to the HoQ is making sure each group answers the same question about the same relationship, What vs How, cell.
Nov 23, 2000 SENG 613 QFD 25
Key Items to Address in HoQ
QFD Team Mission Statement. Who is the customer? What are the Requirements? How important is each requirement? How will you achieve each requirement? Complete the Relationship Matrix (what’s vs how’s). Which how’s are the most important? What are the tradeoffs between the how’s? What target values should be established?
Nov 23, 2000 SENG 613 QFD 26
QFD: Step by Step Guide How QFD Works Step by Step Guide to Build a “House
of Quality” Example:
Web page development
Nov 23, 2000 SENG 613 QFD 27
How QFD Works Customer-requirements-driven design and
production planning process Rationale is that product quality is measured
by customer satisfaction and customers are satisfied if their needs or requirements are met
QFD is building requirements into products. Inputs customer requirements Outputs production procedures for producing a
product to satisfy customers.
Nov 23, 2000 SENG 613 QFD 28
How QFD Works (2)
Conceive
Design Process Production
Requirements
Technical
Specifications
High Level Desig
n
Methods
Tools
QFD Planning Process
Procedures
Nov 23, 2000 SENG 613 QFD 29
House of Quality
Customer Requirements
(Whats)
Relationship Matrix
(Whats vs. Hows”)
Customer Market Evaluation
(Whats vs. Whys)
Degree of Technical Difficulty
Technical Specifications
(Hows)
Correlation Matrix(Hows vs. Hows)
How muchs
Whys
Target GoalsTechnical Competitive
Evaluations
Overall Importance Ratings
Customer
Importance
Rating
Example
Nov 23, 2000 SENG 613 QFD 30
Customer Requirements "Voice of Customer” (VOC) Are “whats” Expressed in customer’s own language Qualitative, vague, ambiguous,
incomplete, inconsistent Group session Categorization and organization
Nov 23, 2000 SENG 613 QFD 31
Technical Specifications Voice of the Engineers or Designers (“hows”). Interpretations of "whats" in terms of technical
specifications or design requirements (designers’ language)
Potential choices for product features Each "whats" item must be converted (refined)
to “how(s)” They have to be actionable (quantifiable or
measurable) Free of technology and implementation creates
flexibility for design
Nov 23, 2000 SENG 613 QFD 32
Relationship Matrix “Whats” vs. “Hows” Correlates how “hows” satisfy “whats” Use symbolic notation for depicting
weak, medium, and strong relationships A weight of 1-3-9 or 1-3-5 is often used More “strongs” are ideal Cross-checking ability
Nov 23, 2000 SENG 613 QFD 33
Customer Prioritization
Prioritizing the importance of each “whats” item to the customer.
Rate each “whats” item in 1 to 5 rating Completed by the customer AHP can be used
Nov 23, 2000 SENG 613 QFD 34
Customer Market Competitive Evaluations
Comparison of the developer's product with the competitor’s products
Question: “Why the product is needed?” The customer evaluates all products
comparing each “whats” item Rating of 1 of 5 is given The results help position the product on
the market. Identify the gaps
Nov 23, 2000 SENG 613 QFD 35
Target Goals “How much’s" of the “Hows“ (measurement) Answers a common design question: "How much
is good enough (to satisfy the customer)?“ Not known at the time when the "hows" are
determined. They are determined through analysis. Clearly stated in a measurable way as to how
customer requirements are met Provides designers with specific technical
guidance Can be used for (acceptance) testing.
Nov 23, 2000 SENG 613 QFD 36
Correlation Matrix “Roof” part Identifies how “hows” items support
(positive) or conflict (negative) with one another
May combine strong positive items to reduce development effort
Find trade-offs for negative items by adjusting “how much” values.
Trade-offs must be resolved or customer requirements won’t be fully satisfied.
Nov 23, 2000 SENG 613 QFD 37
Technical Specifications Competitive Evaluation
Similar to customer market competitive evaluations but conducted by the technical team
Technical advantages or disadvantages over competitor products
Conflicts may be found between customer evaluations and technical team evaluations
Nov 23, 2000 SENG 613 QFD 38
Technical Difficulty Assessment
Performed by technical teams Helps to establish the feasibility
and realization of each "hows" item
1 to 5 ratings
Nov 23, 2000 SENG 613 QFD 39
Overall Importance Ratings
Only time when math is required Calculated overall ratings Function of relationship ratings and
customer prioritization ratings. Used to determine a set of technical
specifications / requirements needed for the next phase.
Nov 23, 2000 SENG 613 QFD 40
Decisions for Phase 2
The “Hows” are analyzed Overall importance ratings Technical difficulties Competitive ratings
Decisions on design requirements are made
Start product design phase
Nov 23, 2000 SENG 613 QFD 41
SQFD
QFD for software Software Engineering is requirements
driven Addresses quality issues in software
development Usually use QFD phase 1 Focuses on requirements “Hows” vs. functional or non-functional
requirements “How much’s” vs. Testing
Nov 23, 2000 SENG 613 QFD 42
How to Apply QFD to SE Use for new or upgrade type of
projects Requirements refinements
Customer has ideal, developer has solution
Ideal to know application domain knowledge Software for internal use Software for general use such as OS, word
processor etc.
Nov 23, 2000 SENG 613 QFD 43
Presentation Summary Disadvantages of SQFD Advantages of SQFD How to Make SQFD work
Nov 23, 2000 SENG 613 QFD 44
Disadvantage of SQFD - What Makes QFD Unsuitable for SE
Time and resources consuming Process limitation in iteration support Does not support common language
between users and developers Documentation requirements Focus on quality other than
functionality
Nov 23, 2000 SENG 613 QFD 45
Benefits of SQFD
Communications among groups Decision justification Metrics Cross-checking Avoid loss of information Shortens the SDLCSource: http://www.acm.org/pubs/articles/journals/cacm/1996-39-1/p41-haag/p41-haag.pdf
Nov 23, 2000 SENG 613 QFD 46
Advantages of SQFD
Customer / User involvement Focus on customer needs Team builder Improve product or service quality Shorter development cycles Lower costs and greater productivity
Nov 23, 2000 SENG 613 QFD 47
Advantages of SQFD (2)
Reduces design changes Good for communication, decision
making and planning Allows for a lot of information in a small
space
Nov 23, 2000 SENG 613 QFD 48
How to Make SQFD Work Obtain management commitment Establish clear, up-front objectives Strong technical know-how Establish multi-functional team. Designate a facilitator QFD training
Nov 23, 2000 SENG 613 QFD 49
How to Make SQFD Work (2)
Get an adequate time commitment from team members
Schedule regular meetings Avoid first using QFD on a large,
complex project Avoid gathering perfect data Avoid technical arrogance Focus on the important items
Nov 23, 2000 SENG 613 QFD 50
Conclusion
QFD originated in the Manufacturing industry and has been applied to software engineering
QFD addresses the quality of the product SQFD is QFD for software QFD, JAD, SSM, PD, RAD and OO all have
their merits and faults The use of the technique depends on the
project
Nov 23, 2000 SENG 613 QFD 51
QFD vs. JAD QFD JAD Type Group session
approach Group session approach
Goal Clients quality need
Improve the system
Driving force Customer voice Human communication
Defect Prevention
Suitable Suitable
Nov 23, 2000 SENG 613 QFD 52
QFD vs. JAD cont.
QFD JAD
Communication/ Cooperation
Software personnel & their users
Users & developers
>10000 users [Capers Jones, 1995]
No such limitations
Not suitable
Nov 23, 2000 SENG 613 QFD 53
QFD vs. JAD cont.
QFD JAD
Focus House of quality Proper communication
Fail Lack of support of Top management
Automated tools are not well & facilitator bypassed