When "Easy to Learn" Isn't "Efficient"

Designing a great user interface is naturally rife with conflicts and compromises. Most design decisions require some choice between two underlying principles—and a decision about which should receive precedence. As I describe in Looking Beyond Design Heuristics, you have to know which rules to emphasize over others given the context, and if necessary, when to break certain rules.

Sometimes, conflicts between principles are not readily apparent. Consider two business requirements which, in some form, are probably part of every employee-facing POS design project:

  1. The point of sale system should be very easy to learn.
  2. Cashiers should be able to conduct transactions quickly and efficiently.

The inherent conflict between these two requirements becomes more obvious when you look at the cashier's expertise level over time. In essence, the interaction strategies that make a system completely intuitive will also likely reduce the user's efficiency in the long term.

With public-facing systems (e.g. web sites, customer kiosks, etc.), interaction designers can often assume that everyone is a perpetual novice. Such an assumption will probably lead to a design that (a) breaks up tasks into smaller chunks, (b) walks the user through more of a predefined process, and/or (c) has a relatively low screen density and uses more screen real estate for instructions and guidance.

However, such a strategy can wreak havoc for the seasoned employee. Smaller chunks means more steps for experts to wade through; a predefined process means less flexibility; and on-screen guidance becomes simple screen clutter once employees become familiar with it. Designers of employee-facing systems must essentially design for two audiences: the novice who needs an easy-to-learn system, and the expert who needs speed and efficiency.

So what to do? Usually, a good approach is to design a user interface that provides features not readily apparent to new users but which they discover over time (see Growing with the User). Depending on the situation, designers can also provide mechanisms to let experts skip steps in established processes—and to let them establish their own processes, if necessary.

While novices are more comfortable with more steps and a greater degree of interaction, experts need to get a high degree of value from a minimal number of interactions (this is the definition of efficiency). Designers can support this need by understanding and supporting the increased ability of experts to take larger amounts of information and see them as connected "chunks"—parts of a larger whole.

Companies should also keep in mind that there may be opportunities for adjusting the user interface over time as expert users develop unforeseen strategies for efficient use. For instance, I traveled to Seattle a few months ago and spent a few days watching cashiers use the new Starbucks POS. As a result of that experience, we made a few tweaks to the interface to support some of the behaviors that began to emerge as cashiers became familiar the system. This evaluation is ongoing.

Resolving the conflict between ease of learning and long term efficiency is sometimes a tough balancing act. But it can be achieved by following the strategies I've outlined—within the context of both the business' and users' needs.