Consistency in the design of digital interfaces aids the user in learning the skills necessary to use the interface effectively. It also aids in the overall likelihood of a user choosing to use a specific interface over another.
Consistency can be broken down into four elements. First, aesthetic consistency, the style and appearance of the interface must be consistent throughout different modes and displays. It also helps a brand become easily distinguished from others. Next is Functional consistency, this is important as it helps users learn how to use an interface by not introducing new symbols or new meanings for the same action. This makes learning easier and people are more inclined to use it. Third is Internal consistency, used to ensure the interface is designed as one, and not thrown together by different people or groups within a company or design group. Lastly, External consistency is an extension of internal consistency, it helps spread the design across the environment and through other independent systems.
There have been arguments against consistency, the primary argument being that too many designers are focusing on whether or not their new designs are consistent with their outdated ones, rather than focusing on ensuring their new designs are in line with their target users current knowledge (Spool, 2005). In this way it could be argued that consistency may limit innovation. A contrary argument to this is that ‘current knowledge is hypothetical most of the time or a statistical measure at best’ (Wrede, 2005). He goes on to say that perhaps the overall learnability of a design and the formal consistency used should be considered over any arbitrary statistic.
Consistency is a strong force in humans. The need for unity and order is innate and is a positive power. This naturally transfers onto our relationships with technology.
Critto, A. (2000). Consistency. In A. Critto, being coherent (p. 3). Maryland: University press of America.
Kidwell, W., Holden, K., & Butler, J. (2003). Universal Principles Of Design. United States: Rockport Publishers.
Wrede, O. (2005, September).Consistency in Design is (part of) the right approach. Retrieved from: http://wrede.interfacedesign.org/archives/1056.html