Parallel Design

A method where several design groups produce alternative designs in parallel, with the objective of incorporating the best aspects of each design in the final solution.

Authoritative References

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.

Online Resources

Usability.gov: Use Parallel Design< Explains the rationale for parallel design.

Nielsen, J., & Faber, J. M. Improving system usability through parallel design<. Originally published in IEEE Computer Vol. 29, No. 2 (February 1996), pp. 29-35. The paper is a case study that provides some data on the cost and and impact of parallel design on the usability of an interface.

Published Studies

Nielsen, J. & Faber, J. M. (1996). Improving System Usability Through Parallel Design<. IEEE Computer Vol. 29, No. 2 , pp. 29-35

Nielsen, J., Fernandes, T., Wagner, A., Wolf, R., and Ehrlich, K. 1994. Diversified parallel design: contrasting design approaches. In Conference Companion on Human Factors in Computing Systems (Boston, Massachusetts, United States, April 24 - 28, 1994). C. Plaisant, Ed. CHI '94. ACM, New York, NY, 179-180.

Ovaska, S. and Raiha, K.J. (1995). Parallel design in the classroom, Proc. CHI 1995, ACM Press , 264-265.

Tohidi, M., Buxton, W., Baecker, R., and Sellen, A. (2006). Getting the right design and the design right. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (Montréal, Québec, Canada, April 22 - 27, 2006). R. Grinter, T. Rodden, P. Aoki, E. Cutrell, R. Jeffries, and G. Olson, Eds. CHI '06. ACM, New York, NY, 1243-1252.

Detailed description

Benefits, Advantages and Disadvantages

Advantages

Allows a range of ideas to be generated quickly and cost effectively.
Parallel nature of the approach 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 solution benefits from all ideas proposed.
Only minimal resources and materials are required to convey product feel.
The technique can be utilised by those with little or no human factors expertise.

Disadvantages

Parallel design requires a number of design team members to be available at the same time to produce the concepts
It requires a major investment of time over a short period for the design work to be carried out.
Time must be allocated to compare parallel design outputs properly so that the benefits of each approach are obtained.

Cost-Effectiveness

Although parallel design might at first seem like an expensive approach, since many ideas are generated without implementing them, it is a very cheap way of exploring a range of possible concepts before selecting the probable optimum.

How To

Procedure

The parallel design method requires design team members to be available concurrently to carry out design work in parallel. A requirements document is needed to make sure that the design groups are given the same information so that design work begins with the same list of user needs.

The following procedure may be adopted for implementing this method:

Define clearly the boundaries for the parallel design, i.e. goal of system, tasks that it should support, user characteristics, etc. Each design team should receive the same set of requirements before starting the design activity..
Each design teams may use whatever media they prefer to present their designs. It is recommended to use a low level of prototyping. No extra points should be given for "sophisticated" prototypes.
Design teams should have roughly equivalent skills.
Decide beforehand how much time to allocate to the design work and set a clear time limit. 10 - 20 hours per group is often sufficient.
Agree on the criteria by which the designs will be assessed.
Allow sufficient time to carry out a fair comparison of the designs produced. This is often carried out in a design workshop, where all groups and their member participate.
Discuss each design separately and then discuss how different aspects of the designs may be combined.
The objective is to settle on one design concept based on the total effort.

The design groups work independently of each other, since the goal is to generate as much diversity as possible. Design groups should not discuss their designs with each other until after they have produced their draft design concepts and presented them in a design workshop. The final design may be one of the designs or a combination of designs, taking the best features from each.

Next Steps

Evaluate the design ideas.

Special Considerations

Facts

Lifecycle: Interaction design