Much of the current research on capturing design rationale is based on variations of the more broadly applicable Issue Based Information System (IBIS), first described by Kunz and Rittel (1970). IBIS stems from an argumentation based model of problem solving and is intended to "guide the identification, structuring and settling o f issues raised by problem solving groups, and provides information pertinent to the discourse ' (JiLunz and Rittel, 1970, p.l) Its original purpose was as a system to characterise, order, and resolve questions raised by co-operative groups of people in administrative government agencies and provide relevant information for the discussion. It was intended to facilitate the organisation and structuring of complex problems and decision processes within organisations, in order that a plan for a solution could be arrived at. Problem solving typically involves deliberation between members of a group, who each have their own expertise and perspectives. A feeling of agreement and a strategy emerges from the deliberation, along with resolutions to the issues at hand.
IBIS offers a solid stmcture with which to explore the deliberation between group members. The legal moves in an IBIS structure can be seen in figure 5.2. The essential elements are issues, positions, and arguments. Issues are questions that require a resolution and an IBIS dialogue always starts with a root issue. The positions are ideas that proffer possible solutions to issues. The arguments are statements which either support or object to the positions. IBIS also incorporates the following relationship types which link the issues, positions and arguments in a hierarchical structure with the main issue at the root: Positions may Respond to
Issues; Arguments may Support Positions; Arguments may Object to Positions; Issues may Generalise other Issues; Issues may Specialise other Issues; Issues may
Replace other Issues; Issues may Question other Issues, Positions or Arguments; Issues may Be Suggested by other Issues, Positions or Arguments.
Through the process of issues being put forward, positions relating to them being stated and deliberation of the positions, a topic is explored and the participants gain an enhanced understanding of the issues. Kunz and Rittel (1970) emphasised that during the process there would be several different types of information being exchanged including a) between the members of the group, b) with the experts used, and c) with reference documentation to support the issues raised. With the more traditional documentation systems, the major problem was that they did not retain any of the structure of the deliberation between the members of a group or the working procedures followed and they did not provide the ability to compare similar issues that may have arisen before. IBIS attempts to combat this lack of expressiveness found in the more traditional systems by making the discussions explicit. Furthermore, using IBIS should actually enhance the whole problem solving process, ensuring that as many avenues as possible are stated, explored and fully considered. IBIS can also be used to demonstrate a snapshot of the state of play of the deliberation between the group at any one moment.
Figure 5.2: Legal moves in IBIS
Source: Conklin and Begeman, 1988, p.305
Generalises, Specialises or Replaces Questions or Is Suggested By ISSUE Questions or Is Suggested By Questions or Is Suggested By Responds To Supports POSITION ARGUMENT Objects To
Figure 5.3 uses the IBIS notation to elaborate some of the issues centering on maintaining brand identity and the role of design values as discussed in sections 2.1.5 and 2.1.6 of Chapter 2. It serves to demonstrate the basic dynamics of the IBIS notation. The same example is executed later with the other two notations discussed in sections 5.3. and 5..4.
Figure 5.3: A S eg m en t o f an IBIS D ia lo g u e Issue: How to maintain brand identity? Supports Responds to 'bjects to Responds to Specialises Issue: How to ensure consistent design values? ^ Responds Is suggested R esponds Issue: ^
How to develop a framework to a s s e s s if new ranges hold appropriate design v a lu e s? ^
Supports s suggested
Questions Supports
Issue:
How to define the design vaiues? Responds to Position: Use strong advertising. Position: Rationalise product ranges. Position:
Use repertory grid and other knowledge elicitation exercises. Position: Maintain a multimedia design rationaie representation. Position: Frequently communicate the design vaiues to all personnel in the company.
Argument;
May restrict entering new market areas. Argument:
Ensures clear picture of product offering to consum ers.
Argument:
Acts a s a valuable precursor to setting the design brief.
^
Argument: Ensures all personnel hold the sam e belief system in relation to the , product desiqn.As outlined earlier, IBIS is intended to organise the process of handling problems in ill-structured domains, modeled in terms of an argumentation structure. In section 2.2 of chapter 2 the product design process was indeed shown to be such an ill structured domain, where issues do not lend themselves to a sequential approach to problem solving. Previous investigations into the usefulness of IBIS to structure product design rationale have focussed on engineering design domains. Its application to the context of design deliberation, takes the form of a network representation of the various alternatives that are considered in response to issues and the arguments for and against the positions (Moran and Carroll, 1991). Often the understanding of design problems evolves as the solution is worked on. 'IBIS attempts to capture the issues that arise in the course o f design deliberation, along with the various positions (or alternatives) that are raised in response to issues and the arguments for and against the positions. Keeping track o f such a network supports the recall of decisions and their rationale. This makes the decisions more understandable to designers at a later time and exposes them to reflection and reconsideration.^(Moran
and Carroll, 1991, p. 198) IBIS supports the representation of a complex network of issues, positions relating to them and their justifications. In a design conversation certain issues may be touched on briefly and then remain unresolved or explored. It requires the skill and knowledge of a designer to filter the critical issues in the network from the mundane.
Conklin and Begeman (1988) proposed several extension to the IBIS method in their hypertext ‘graphical IBIS’ (gIBIS), as demonstrated in figure 5.4. The gIBIS tool was developed to capture design deliberations and uses a graphical window to enable hypertext networks of the gIBIS nodes and links to be constructed and navigated. It utilises IBIS as the underlying notation but incorporates additional node types and uses colour hypertext maps to facilitate the construction and navigation of IBIS networks. An additional, more generic node and link type, 'Other', is incorporated in gIBIS as an option to be used where difficulty is being experienced with the ridgity of the IBIS framework. An External node type is also proposed in order to contain links to external files, such as briefs, sketches, meeting minutes. Further flexibility is added in gIBIS by allowing positions to specialise or generalise other positions and likewise arguments. The ability to create submaps as an entity is also incorporated into the
graphical tool Conklin and Begeman used to build their gIBIS networks. These submaps may be moved about or aggregated and made into a single node with the facility to be expanded to the full map as desired by the user. Within this node a marker is provided to flag whether or not a resolution had been reached for the issue at the root of the submap. This can be contrasted with IBIS which does not signal issue resolution.
Figure 5.4: Legal moves in gIBIS
Source: Conklin and Begeman, 1988, p.305
Generalises, Specialises or Replaces Questions or
Is Suggested By Any node type
ISSUE Other OTHER Questions or Is Suggested By Questions or Is Suggested By Responds To Supports POSITION AR G U M ENT Objects To Specialise or Generalise Specialise or
Generalise Any node type
EXTERNAL
Two main categories of use were identified for the gIBIS tool: a) as an isolated hypertext tool for structured thinking and design; and b) as a vehicle for structured communication (Conklin and Begeman, 1998). Conklin and Begeman concluded that there is a close correlation between some of the cognitive structures and processes of design and the node and link types that compose IBIS. However they also identify shortcomings that require addressing, namely the lack of a node type for goals and requirements, the lack of support for denoting a decision or consensus for issues and the ability to link data on artefacts to the decisions that led to them.