[ 2] http://www.transi-tionrig.com

Now consider another alternative, a sail configuration called the transition rig, invented by Richard Dryden [ 2]. The transition rig is modeled after a bat’s wing; it provides a series of joints and folds in a variable geometry that can adjust easily and automatically to changing wind conditions. Of course, the International 470 can also react to changing weather conditions, but it requires many individual control lines to achieve the same effect.

Although sailing with the transition rig is more straightforward, manufacturing it is not. The transition rig requires a rotating base and several complicated joints constructed from carbon fiber and stainless steel. Dryden identified a user need (ability to adjust sail shape) that was being met, but with a complex set of controls. He chose to focus engineering efforts on meeting the same need, but with a product that is less complex to use and operate.

What has happened here? Functionality remains the same—the sail changes shape to adjust to wind conditions. The complexity has been restructured in the transition rig’s design: Dryden shifted the complexity from the use of the product to its design and construction.

In this case it’s impossible to remove individual features (i.e., removing the vang would make controlling the twist of the sail difficult). The new design doesn’t try to remove features or limit the functionality of the sailboat. In many cases, and for mature products, this is a desirable trade-off. Where the complexity provides critical functionality, it can be shifted out of the user

experience into manufacture— thus tamed.

Shifting the complexity away from the user and onto the system may be the best alternative to simply removing features. This shift can be accomplished through active automation ( completing your taxes in Turbo Tax), system manufacturing (the transition rig), or simply a new design metaphor (archiving mail by conversations rather than dates). As computers get more powerful, materials more advanced, and methods more sophisticated, it makes sense to move more of the burden from the user to the product. This is true of all types of products, whether they are physical products, software, hardware, or even websites.

[ 3] ISO 13407, “ Human-centered design processes for Interactive systems,” 1999.

Conservation of
Complexity in Action

What methods can be applied to combat complexity? How, specifically, can complexity be “moved” so it’s no longer a burden on users? How do we handle complexity at design time so it can be tamed once rather than having each individual user puzzle it out every time?

At a high level, the principles of human-centered design espoused in ISO standard 13407 are completely on target [ 3]:

• The active involvement of users and a clear understanding of user and task requirements. By understanding what users need to do, designers can determine where to focus their efforts, which features to make prominent, which features to remove, and they can begin to determine navigation paths within a user interface that are aligned to the users’ tasks.

• The iteration of design solutions. Nobody can burp up a perfect design on the first try; it takes a number of successive approximations, testing alternatives against one another, and a graveyard of failed attempts to design something worthwhile. Design concepts must be tested with users to see how they fare and to determine where changes should be made.

• Multidisciplinary design. Design of usable systems takes a variety of skills. Just as in the example of Dryden’s transition rig, you can imagine that expertise in sailing, aerodynamics, metallurgy, mechanics, textiles and sail-making, even biology, is needed—his rig looks to bat wings for inspiration. User-interface and product designers must bring a broad range of skills to bear on a problem and need to collaborate with many other disciplines.

• The appropriate allocation of function between users and technology. People and technology are good at different things. People exhibit judgment but have quite limited short-term memory. It’s stunning how quickly computers can perform calculations, but they’re poor at recognition, error recovery, and dealing with incomplete information.

In the case of the mailing equipment, where customers were calling to request features that were already present, we were asked to step in and help rectify the situation. We had to take the system apart ( metaphorically), organize it, and put it all back together again in a rational, organized fashion. We modeled the information structures visually to diagram the user’s mental model. This information-architecture work organizes and