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Elegance, Simplicity, Flexibility &
Change: Resisting Design Erosion

(SIGCHI Bulletin March/April 2003 )

Kevin Mullet and Darrell Sano’s Designing Visual Interfaces includes a very enlightening chapter on elegance and simplicity, describing the basic principles as unity – a minimal set of intimately related parts with a clear contribution to a common goal; refinement – removal of elements that do not contribute to the task of communication; and fitness – suitability to a particular purpose through avenues that are desirable in their own right.

Edward de Bono has written a whole book on the subject of simplicity, culminating in the following ten rules:

1. You need to put a very high value on simplicity
2. You must be determined to seek simplicity
3. You need to understand the matter very well
4. You need to design alternatives and possibilities
5. You need to challenge and discard existing elements
6. You need to be prepared to start over again
7. You need to use concepts
8. You may need to break things down into smaller units
9. You need to be prepared to trade off other things for simplicity
10. You need to know for whose sake the simplicity is being designed

Clearly, elegant and simple designs do not happen by accident. To make matters worse, for interactive systems – especially those in the volatile world of e-commerce – fitness or suitability is a constantly moving target, requiring relatively constant change just to remain current. Unfortunately, change has an eroding effect on design, with simplicity usually the first to succumb to effects of ad hoc solutions, creeping featurism and poor understanding of users’ needs. I believe de Bono’s ten rules do a good job of addressing these problems in general terms, but I would like to expand on the fourth rule by introducing the concept of flexibility. As in the natural world, flexibility is an effective defense against erosion. Flexible solutions require fewer changes than those which were merely adequate for the problem as it was understood at the time. And because flexible solutions are designed with alternatives and future possibilities in mind, when change is required, it is less damaging in terms of simplicity and elegance.

Let’s consider an example. Most e-commerce sites allow users to select between a number of stored credit cards during checkout. Why? At the simplest level, we are mimicking what customers can do at a bricks-and-mortar checkout, so we might not be inclined to think any more about it. But if we are looking for a flexible solution, which might anticipate future developments in e-commerce, we should dig a little deeper. What drives customers’ choice of credit card in their wallets or purses? Are they trying to spread their spending to keep within credit limits? (In which case, wouldn’t it be nice if we could put the balance and credit limit for each card on the page?) Perhaps some customers use different cards for different purposes – business, personal, club or similar? Can we learn any more from this that might help us to design a flexible solution? I believe so. I think it tells us that customers might be acting in different roles when they visit our site. Why not acknowledge this in the design and allow them to create or choose a shopping basket for each purpose? That way they could shop for different purposes simultaneously, without having to sort out the mess themselves at the checkout. (“I want these three items on this card to that address and those two items to the same address, but a different card, etc.”) They would just select which basket each item was to be placed in. The basket would have default delivery and payment information associated with it much as the single basket solutions do now. But simple, elegant and flexible solutions like this get us more than just a little added convenience. They also have the potential to improve other aspects of design by more realistically reflecting our users’ behaviors. So instead of getting a complete mix of purchasing recommendations based on everything I have ever bought for anyone from a site, I would get recommendation based on the shopping basket I am currently using. So no more pointless promotion of S Club Seven CD’s after my annual purchase of a birthday present for my daughter.

As with most things, the rewards for this extra attention to flexibility can vary dramatically. The nature of flexible solutions can also vary – some will simply be adaptable, others may allow a greater range of user control and customization. However, given the high cost of design erosion in interactive systems, especially where ad hoc development methods prevail, a little more effort spent in early design and discovery – with an emphasis on elegance, simplicity and flexibility – will normally pay dividends.


Edward de Bono (1999), Simplicity, Penguin Books, London (also at Amazon.co.uk)

Kevin Mullet and Darrell Sanos (1994), Designing Visual Interfaces, Prentice Hall, Englewood Cliffs, NJ (also at Amazon.co.uk)

The Author

William Hudson is principal consultant for Syntagm Ltd, based near Oxford in the UK. His experience ranges from firmware to desktop applications, but he started by writing interactive software in the early 1970's. For the past ten years his focus has been user interface design, object-oriented design and HCI.

Other free articles on user-centred design: www.syntagm.co.uk/design/articles.htm

© 2001-2005 ACM. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in SIGCHI Bulletin, {Volume 35, March-April 2003} http://doi.acm.org/10.1145/967199.967211

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