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GW, Chapter 1 Methodologies Arent Enough
Software SpecificationLecture 6

• Prepared by
• Stephen M. Thebaut, Ph.D.
• University of Florida

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Part I Negotiating a Common Understanding

• Methodologies Arent Enough
• Ambiguity in Stating Requirements
• Sources of Ambiguity
• The Tried but Untrue Use of Direct Questions

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Methodologies Arent Enough

• Some would argue that ...in order to do a
  better requirements job...remove the people from
  the process and instead use a methodology.
• Today,...packaged methodologies flood the
  market...
• So ...who needs a book about people-oriented
  tools?

Software Specification GW Chapter 1
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Consider the Guaranteed Cockroach Killer...

• Whether its roaches or requirements, the hard
  part is catching them and getting them to stand
  still.
• Even with guaranteed methodologies, ...youll
  still need the tools described in this book.

Software Specification GW Chapter 1
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Methods Effect on Problems

• "Because there are now superior tools and
  methods, developers attempt systems that never
  could have been imagined (before).
• ...problems that are most amenable (to our
  superior tools and methods) are quickly
  eliminated, leaving a residue of messy
  problems...

Software Specification GW Chapter 1
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Notations and Maps

• Notation a symbolic way of representing systems
  ideas.
• The exploration metaphor leads to the term map.
• The use of multiple notations ...can be useful,
  and even necessary.
• An important property of maps ease of revision.

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Making Sure Everyone Can Read the Map

• The most important property of a map every-one
  involved should be able to understand it.
• Claims that someones favorite notation is
  intuitive or easy to read are true in the
  same sense that Cantonese is intuitive in
  Hong Kong.

Software Specification GW Chapter 1
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Exercises to Facilitate Notation Familiarization

• Have each map presented by someone who does not
  know the notation.
• Ask each person to translate a map from one
  notation to another.
• Use a CASE or CAD system with several embedded
  notations and the ability to transform a map from
  one to the other, instantly.

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Exercises to Facilitate Notation Familiarization
(contd)

• Delay the start of requirements work until
  everyone has attended a course on the common
  notation.
• or
• Conduct the class as part of the requirements
  meetings, perhaps keyed to specific examples from
  the system being developed.

Software Specification GW Chapter 1
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Maps of Requirements Are Not Requirements

• When the map and the territory dont agree,
  always believe the territory.
• We have to work with maps, but maps arent
  perfect. They often under- or over-constrain
  requirements.

Software Specification GW Chapter 1
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Helpful Hints and Variations

• Problem dealing with users wishing to get all
  their wishes met but unwilling to commit time to
  the requirements process.
• A reason for this problem treating customers in
  a patronizing manner. (Most participants are
  naive only about the development process, and
  they are experts themselves in subjects about
  which the designers are naive.)

Software Specification GW Chapter 1
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Helpful Hints and Variations (contd)

• Methodology experts underestimate the difficulty
  of understanding their notations...
• When two sets of experts participate in the same
  requirements process, theres often a conflict
  about...notation... (...experts often share a
  first love syndrome for notations.)

Software Specification GW Chapter 1
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Helpful Hints and Variations (contd)

• The Swiss example all notations that are first
  love notations are official. (Indeed, in
  Swiss meetings, people from the dominant
  language group often present their ideas in the
  secondary languages, ...as a strong indication
  of how much they value their participation.)

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Helpful Hints and Variations (contd)

• A reminder ...value can be added at any stage
  of...product development requirements are only a
  guide. They are to be taken literally, but not
  too literally. There are many roads to Paradise.
• Always be prepared to go back and revise (the
  map) when further exploration shows that there
  was a wrong branch higher in the decision tree.

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Summary Avoiding Communication Problems

• Dont leave all the hard parts to be handled by
  someone else, as in the Guaranteed Cockroach
  Killer kit.
• ...Dont underestimate the difficulties for some
  people in adapting to new methods and new
  notations.
• (different) mapping techniques will appeal in
  different ways to (different participants).
  ...dont try to force people to conform or
  belittle them for being stupid.

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Summary Avoiding Communication Problems (contd)

• ...make sure at every step that everyone can
  read the map in order not to exclude anyone.
• If you find yourself getting touchy about
  notational nuances, remember that the map is not
  the territory...

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GW, Chapter 1 Methodologies Arent Enough
Software SpecificationLecture 6

• Prepared by
• Stephen M. Thebaut, Ph.D.
• University of Florida