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Use Parallel Design
- What is parallel design?
- What are the benefits of parallel design?
- How have others conducted parallel design?
- How does parallel design work?
What is parallel design?
With parallel design, several people create an initial design from the same set of requirements. Each person works independently, and when finished, shares his/her concepts with the group.
The design team considers each solution, and each designer uses the best ideas to further improve their own solution. This process helps to generate many different, diverse ideas and ensures that the best ideas from each design are integrated into the final concept. This process can be repeated several times until the team is satisfied with the final concept.
What are the benefits of parallel design?
Several research projects have shown the value of this technique:
- Seeing and trying others' designs improved final solutions
- Creating many designs produced better results
- Combining design elements resulted in better user interfaces
Seeing and trying others' designs improved final solutions
Bailey (1992) reported on training courses where students were given a specification and used a prototyping tool to create a simple system. After all the students completed their designs, each student used everyone else's system to complete a task. Having experienced the ideas of all the other students, each then made changes to his or her original prototype. This process was repeated two more times. The revised interfaces were always considerably better than the originals. Two important observations emerged from these classes:
- No matter how good the original interfaces were, every one was improved.
- Students were able to very quickly identify the good design ideas in the systems of others, and they effectively integrated those good ideas into their own designs.
Creating many designs produced better results
A few years later, Nielsen (1993) described a development methodology in which several designers worked independently to generate as many different design ideas as possible. Once they had created different designs, they combined their different ideas and took the best features from all designers. The goal was to develop and evaluate different ideas before settling on a single approach.
Nielsen listed the following as major benefits of this approach:
- It allows a range of ideas to be generated quickly and cost-effectively.
- It allows several approaches to be explored at the same time, thus compressing the concept development schedule.
- The concepts generated can often be combined so that the final product benefits from all the proposed ideas.
- People with little usability expertise can use the technique.
Combining design elements resulted in better user interfaces
A few years later, Ovaska and Raiha (1995) published an article suggesting that having designers make initial design decisions independently and then combining their results produced better user interfaces than the original design of any one person. They called this approach "parallel design."
How have others conducted parallel design?
McGrew (2001) published an article confirming the value of parallel design. McGrew's case study was the user interface for an invoice reconciliation program. He scheduled a one-day session with several participants, including the project manager, a designer, two subject matter experts, a technical writer who was scheduled to do the training, three users, and a human factors engineer.
They began by having each person independently sketch a proposed user interface on a large sheet of paper using colored felt-tip markers. The sketches then were posted on the wall for all to see and evaluate. After viewing the design solutions proposed by others, each participant sketched two new designs. McGrew required that each new design include at least one idea from another person's design and an idea that no one had yet proposed. Again, all participants reviewed all the design solutions. They began to agree on an optimal design fairly early in the process and were able to reach consensus on the final user interface before the end of the day.
How does parallel design work?
What is most striking about parallel design is how many ideas can be considered in a very short time. Most linear processes would only have considered a few iterations of a single design in the time that parallel design can consider many ideas. McGrew's design team considered at least 40 design alternatives in a single day. McGrew found that most participants responded immediately to good ideas. This was true even when good ideas were contained in otherwise poor design solutions.
Good user interface design requires designers first to "saturate the design space." This means that user interface designers should consider as many alternative design ideas as possible before selecting the best to take forward.
References
Bailey, R.W. (1992), Learning good design from the decisions of others, User Interface Update - 1992.
Macbeth, S.A., Moroney, W.F., and Biers, D.W. (2000), Development and evaluation of symbols and icons: A comparison of the production and focus group methods, Proceedings of the IEA 2000/HFES 2000 Congress, 327-329.
McGrew, J. (2001), Shortening the human computer interface design cycle: A parallel design process based on the genetic algorithm, Proceedings of the Human Factors and Ergonomics Society 45th Annual Meeting, 603-606.
Nielsen, J. (1993), Usability Engineering. Boston: Academic Press.
Ovaska, S. and Raiha, K.J. (1995), Parallel design in the classroom, Proceedings of CHI'95, 264-265.
Next steps
Once you have a preliminary site structure from Card Sorting, content to write for the web, and a preliminary design, you can create a prototype to evaluate and test. Learn About Evaluations to select the right one for your current needs. Learn About Usability Testing so that you can start an iterative series of usability tests.
