Software Quality Function Deployment - University of Alberta

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					      Quality Function Deployment
                         David Menks
                         Anwar Ahmed
                           Kaijun Fu
Found at:
       Other Sources on QFD/SQFD

   Good overview can be found at:

   Downloadable tool:

   SQFD paper: (see other slides)

     Nov 23, 2000                 SENG 613 QFD                           2
      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              3
      Overview of QFD
    The History of QFD.

    What is QFD?
    Why use QFD?
    Characteristics of QFD?

    Nov 23, 2000      SENG 613 QFD   4
      History of QFD
    1960‟s, Yoji Akao conceptualized QFD.
    Statistical Quality Control, SQC, was the
     central quality control activity after
    SQC became Total Quality Control,
    QFD was derived from TQC.

    Nov 23, 2000      SENG 613 QFD               5
      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                6
      QFD Takes Hold
    The first paper on QFD was published in
    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            7
      QFD in North America
    QFD spread rapidly in North America during the
    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               8
      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               9
      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

    Nov 23, 2000       SENG 613 QFD                10
      Overview of QFD
    The History of QFD.

    What is QFD?

    Why use QFD?
    Characteristics of QFD?

    Nov 23, 2000      SENG 613 QFD   11
      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              12
      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              13
      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               14
      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               15
      Overview of QFD
    The History of QFD.
    What is QFD?

    Why use QFD?

    Characteristics of QFD?

    Nov 23, 2000      SENG 613 QFD   16
      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,

    Nov 23, 2000     SENG 613 QFD              17
Nov 23, 2000   SENG 613 QFD   18
      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

    Nov 23, 2000         SENG 613 QFD                 19
      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
    You are seeking long term savings in
     that product or the products that follow.

    Nov 23, 2000      SENG 613 QFD               20
      Overview of QFD
    The History of QFD.
    What is QFD?
    Why use QFD?

    Characteristics of QFD?

    Nov 23, 2000     SENG 613 QFD   21
      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              22
      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            23
      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               24
      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                    25
      QFD: Step by Step Guide
    How QFD Works
    Step by Step Guide to Build a “House of
    Example:
         Web page development

    Nov 23, 2000        SENG 613 QFD           26
      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               27
               How QFD Works (2)

                             Technical                                      Methods
                                                     High Level                                    Procedures
Requirements               Specifications                                    Tools
                Conceive                    Design                Process             Production

                                            QFD Planning Process

        Nov 23, 2000                                 SENG 613 QFD                                           28
  House of Quality

                             Correlation Matrix
                              (Hows vs. Hows)
                          Technical Specifications                     Whys
         Customer               Relationship               Customer           Customer
       Requirements               Matrix                  Importance           Market
                                                            Rating            Evaluation
         (Whats)             (Whats vs. Hows”)
                                                                        (Whats vs. Whys)
                      Technical Competitive Evaluations
       How muchs                 Target Goals
                        Degree of Technical Difficulty                    Example
                         Overall Importance Ratings

Nov 23, 2000                           SENG 613 QFD                                        29
      Customer Requirements
    "Voice of Customer” (VOC)
    Are “whats”
    Expressed in customer‟s own language
    Qualitative, vague, ambiguous, incomplete,
    Group session
    Categorization and organization

    Nov 23, 2000        SENG 613 QFD              30
      Technical Specifications
    Voice of the Engineers or Designers (“hows”).
    Interpretations of "whats" in terms of technical
     specifications or design requirements (designers‟
    Potential choices for product features
    Each "whats" item must be converted (refined) to
    They have to be actionable (quantifiable or
    Free of technology and implementation creates
     flexibility for design

    Nov 23, 2000           SENG 613 QFD                  31
      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             32
      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               33
      Customer Market Competitive
    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
    Identify the gaps

    Nov 23, 2000        SENG 613 QFD                34
      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
    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                    35
      Correlation Matrix
   “Roof” part
   Identifies how “hows” items support
    (positive) or conflict (negative) with one
   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               36
      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             37
      Technical Difficulty
    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           38
      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              39
      Decisions for Phase 2
    The “Hows” are analyzed
         Overall importance ratings
         Technical difficulties
         Competitive ratings
    Decisions on design requirements are
    Start product design phase

    Nov 23, 2000          SENG 613 QFD      40
    QFD for software
    Software Engineering is requirements driven
    Addresses quality issues in software
    Usually use QFD phase 1
    Focuses on requirements
    “Hows” vs. functional or non-functional
    “How much‟s” vs. Testing
    Nov 23, 2000        SENG 613 QFD               41
      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
         Software for internal use
         Software for general use such as OS, word
          processor etc.

    Nov 23, 2000          SENG 613 QFD                 42
    Presentation Summary
   Disadvantages of SQFD
   Advantages of SQFD
   How to Make SQFD work

Nov 23, 2000      SENG 613 QFD   43
      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               44
      Benefits of SQFD
    Communications among groups
    Decision justification
    Metrics
    Cross-checking
    Avoid loss of information
    Shortens the SDLC

    Nov 23, 2000                               SENG 613 QFD                              45
      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        46
      Advantages of SQFD (2)
    Reduces design changes
    Good for communication, decision making
     and planning
    Allows for a lot of information in a small

    Nov 23, 2000        SENG 613 QFD              47
      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       48
      How to Make SQFD Work (2)
    Get an adequate time commitment from team
    Schedule regular meetings
    Avoid first using QFD on a large, complex
    Avoid gathering perfect data
    Avoid technical arrogance
    Focus on the important items

    Nov 23, 2000      SENG 613 QFD               49
    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

    Nov 23, 2000       SENG 613 QFD                 50
  QFD vs. JAD
              QFD                   JAD
Type          Group session         Group session
              approach              approach
Goal          Clients quality       Improve the
              need                  system
Driving force Customer voice        Human
Defect         Suitable             Suitable
Nov 23, 2000         SENG 613 QFD                   51
    QFD vs. JAD cont.
                 QFD                  JAD

Communication/   Software    Users &
Cooperation      personnel & developers
                 their users
>10000 users     No such     Not suitable
[Capers Jones,   limitations

  Nov 23, 2000         SENG 613 QFD         52
   QFD vs. JAD cont.
                QFD              JAD

Focus           House of quality Proper communication

Fail            Lack of support Automated tools are not
                of Top          well & facilitator
                management      bypassed

 Nov 23, 2000                SENG 613 QFD                 53