Useful designs and systems are essential for all users, and consistency a significant factor towards achieving this. Consistency is defined as what helps people with transferring knowledge, learning new things quickly, and focusing on relevant aspects of a task (Lidwell, Holden & Butler, 2003). There are four kinds of consistency: aesthetic, functional, internal, and external.
Firstly, consistency is needed for good design, as is aesthetic consistency. This is composed of style and appearance, and helps users to recognize brands and their associated value, or enhance consumer’s perspective of purchase. Companies use the same color, fronts, and icons throughout their marketing materials so that customers can experience consistent recognition and association (DiMarco, 2010, p. 51). Thus, aesthetic consistency is significant for good design which can attract customers.
Secondly, aesthetic consistency helps achieve a good design through functional consistency. This refers to products of products of the same type used in similar ways and designs. The consistency of function enables user to learn the tips within a new environment. DiMarco (2010, p. 51) also explains this saying that functional consistency leads to creating implied meaning for users and they can be transparently guided by hierarchy.
Thirdly, consistency is used for a good system as internal consistency. This means consistency which can be seen with other elements in the system. According to Zuschlag (2010), users ‘can generally count on your products being regarded as its own cognitive context within the larger context of common metaphors, as well as other products and operating systems’. Also, functional consistency must be involved within any logical grouping elements.
Lastly, consistency that is important for good designs is external consistency. This explores the merit of internal consistency to outside, but it is hard to make. Cole (2012) claims that learning on external convention is useful nevertheless the difficulty of breaking away from what others are doing.
In conclusion, there are four elements of consistency: aesthetic, functional, internal and external. Each one of these elements are essential for a good, functional system.
Cole, D. Why Is Consistency Important in Design? Retrieved from http://www.slate.com/blogs/quora/2012/12/24/why_is_consistency_important_in_design.html
DiMarco, J. (2010). Digital design for print and web: an introduction to theory, principles, and techniques. Retrieved from http://www.eblub.com.au/
Lidwell, W., Holden, K., & Butler, J. (2003). Aesthetic‐Usability Effect. In Universal Principles of Design (pp. 46). Massachusetts: Rockport.
Zushlag, M. (2010). Achieving and Balancing Consistency in User Interface Design. Retrieved from http://www.uxmatters.com/mt/archives/2010/07/achieving-and-balancing-consistency-in-user-interface-design.php#sthash.UE8AAD7x.dpuf