Problems of Design

1
Problems of Design

• design spans many disciplines
• design is often a group activity
• not a sequence of well defined activities
• it involves a lot of cognitive activity
• ideation
• learning
• problem solving
• decision making
• group design involves distributed cognitive
  processes and shared understanding
• design problems are often wicked (Rittel)

2
Wicked Problems according to Rittel

• 1. There is no definite formulation. The
  information needed to understand the problem
  depends on one's ideas for solving it. In order
  to describe a wicked problem in sufficient detail
  one has to develop an inventory of all
  conceivable solutions ahead of time. To find the
  problem is to find the solution. Wicked problems
  require a 'second generation' (argumentative)
  methodology to deal with them.
• 2. They have no stopping rule. Completion is
  determined by time, money, patience and the
  feeling that the solution is 'good enough'.
• 3. Solutions are not true or false, just good or
  bad. Judgement of the 'goodness' is subjective
  and will vary within any group.
• 4. There is no ultimate test of the solutions.
  They will have consequences over a period of time.

3
Wicked Problems (continued)

• 5. There is no opportunity to learn by trial and
  error, every attempted solution counts
  significantly and leaves traces which cannot be
  undone.
• 6. They do not have an enumerable set of
  solutions.
• 7. Every wicked problem is essentially unique. It
  is never possible to be sure that the particulars
  of a specific problem do not over-ride the
  commonalities with other, apparently similar,
  problems. Part of the art of dealing with such
  problems is not to apply standard solutions too
  early.
• 8. Every wicked problem can be the symptom of
  another problem. There is no natural level at
  which a problem should be tackled it relies on
  the self confidence of the analyst. A problem
  solved at too low a level may make it more
  difficult to deal with higher level problems.

4
Argumentative Design

• Rittels second generation design methodology
• recognises interdependency of problem and
  solution
• you cannot understand the problem without having
  a concept of the solution in mind'
• 'you cannot gather information meaningfully
  unless you understand the problem, but you cannot
  understand the problem without information about
  it'.
• brings about a better solution by utilising the
  distributed expertise of a group who can bring
  differing viewpoints to bear on a problem
• involves those who will be subjected to the
  solution, to facilitate the implementation of
  that solution.

5
Supporting Argumentative Design

• argumentation can be complex
• can range over many areas
• can take place over extended periods
• often revisits the same areas
• composition of teams may change over time

6
Design Rationale

• Various definitions exist including
• 1) A historical record of the reasons for the
  choice of an artefact. BurgessYakemovic 1990
• 2) A description of a design space MacLean 1989
• Essentially DR can be thought of as answering the
  questions
• 1) Why is this artifact designed the way it is?
• 2) How might it be designed differently?

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Justification for Design Rationale

• makes argumentation explicit
• might act as a cognitive aid to design
• facilitates communication between designers
• facilitates design re-use
• facilitates maintenance or redesign
• provides a history or audit trail

8
Issue-based Information System (IBIS)

• originally proposed by Rittel, refined by Conklin
  and others.
• based on ideas of argumentation.
• may be used in real-time meetings.
• more frequently used to summarise meetings after
  the event.
• both graphical (gIBIS) and textual forms
  (itIBIS).
• describes why an artifact is the way it is.

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IBIS Structure
figure The set of legal rhetorical moves in
IBIS from 'Design Rationale and Maintainability'
by J Conklin
10
Design Space Analysis (DSA)

• developed by McLean et.al. (Xerox Labs).
• extends the concept of a design to a range of
  possible solutions from which one may be chosen.
• helps to make explicit the rationale behind a
  design.
• can be an effective communication aid between
  members of a design team.
• can act as a cognitive tool to clarify thought.
• describes how an artifact might be different

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Questions, Options and Criteria (QOC)

• QOC is the notation used for DSA
• Questions represent the key issues for
  discussion.
• Options are the alternative design choices
  available.
• Criteria are either requirements or desirable
  features which the design might have.

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A Real QOC Example(deciding the attributes of a
scroll bar in a Windowing system)
(From MacLean91)
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Drawing QOC

• try to formulate a set of key design questions
  which will contribute to solving the problem
• derive a set of criteria from the information
  known. Criteria may be required features or
  things which the designers think are desirable.
• generate options which may satisfy the questions
  and assess each option against relevant criteria,
  both positively and negatively.
• dont try to cross reference criteria between
  different questions, repeat them if necessary
• generate consequent questions and new criteria
  where necessary

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QOC in Decision Making
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Disadvantages of Design Rationale

• imposes an additional cognitive overhead on the
  design process
• may inhibit discussion
• may have legal implications