Grudin: The Case Against User Interface Consistency

by Carson Reynolds

Many expert’s heuristics and experimental results support consistency. However we must first define consistency, discriminate between different approaches to consistency, and determine when other concerns overshadow it. Consistency, however, has proven a difficult to define. The article argues that consistency ought not to be the designer’s primary concern, but rather “users and their work.” Interestingly, Grudin sees those interested in consistency because of the “possibility of automating the design and evaluation of some aspects of interfaces.” However, he sees consistency as a “largely unworkable concept.” The article moves ahead to present examples where interface inconsistency improves usability.

Grudin articulates 3 types of consistency:

  • Internal consistency of an interface design.
  • External consistency of interface features with features of other interfaces familiar to the users.
  • Correspondence of interface features to familiar features of the world beyond computing.

Grudin moves on to argue that while consistency supports ease of learning, it is in conflict with ease of continued use. After examining different possible keyboard arrangements, Grudin concludes that consistent, learnable interfaces are a hinderance to continued ease of use. After further examining different consistent rules that could be applied to menu defaults, Grudin finds that “no tool to produce or check for interface consistency cold handle this interface design, unless it contained detailed knowledge of the users.”

Grudin concludes by seeking a synthesis of consistency and inconsistency. He argues that task considerations should override consistency, but retreats from this a bit. But mainly he argues that better understanding of users and their work environments will help interface design more than monomaniacal application of guidelines.