Information Architecture is not Usability
In: Columns > IAnything Goes
Published on November 5, 2002
The distinction between information architecture and usability may seem like semantics, but there are significant differences between the two disciplines. Though they are often discussed interchangeably, and practitioners are often well-versed in both, information architecture and usability differ in their scope and areas of focus.
The difference between information architecture and usability is vital to understand, because, as discussed last month, information architecture is more than just understanding what users want and need. A usability-only approach to IA is only one piece of the puzzle. Information architecture problems often account for a large percentage of usability problems, but there are many other things unrelated to IA that have an impact on usability.
To paraphrase Peter Morville, information architecture is a subset of usability, and usability is a subset of information architecture.
Information Architecture as a Subset of Usability
Usability is a detailed subject, taking into account things like font size, colors, visual proximity, usage context, search, error messages, navigation, form design, and labeling. Of these, only a few are true information architecture issues. Navigation, labeling, site architecture and search results all have an impact on the usability of a site, but they are not the only things that affect usability.
A small font size or poor choice of color contrast may make a site hard to use. Lengthy text in "marketing speak" or badly written error messages can cause problems for users as well. Lack of proper bandwidth or inefficient calls to databases can slow down response times, negatively impacting the user experience.
While these are certainly things that someone responsible for the information architecture of a site should be aware of, they don't fall under the formal umbrella of information architecture. Font size and color choice are usually left to the graphic designer. Writers should be responsible for improving copy, and those on the technical side are best equipped to address speed issues related to technology problems.
It may be that one of these people is also acting as an information architect, and possibly even covering some other responsibilities. In these cases, it is important to understand that the information architect's role is not necessarily the same as the information architect job title. Balancing information architecture and usability concerns with other responsibilities is a difficult task, but a thorough understanding of the various concerns can lead to appropriate compromises. Each decision must be made with an understanding of how it will effect usability, business concerns, technical constraints, and other relevant aspects.
Fixing usability problems might in some cases be best served by changes to information architecture issues (changing the navigation scheme, modifying the page architecture), but may also be rectified by changes to other elements that make up the user experience. Remember, there is more to usability than just information architecture, and there is more to information architecture than just usability.
Usability as a Subset of Information Architecture
In the absence of a usability specialist, those filling the information architect role are the next most likely to be user advocates for two reasons:
Designing for users is an inherent part of information architecture, and is not necessarily so for other roles on a web development team.
People don't understand the difference between information architecture and usability and assume they are the same.
Ideally, others on the team should be aware of usability issues and best practices, but this is not always the case. Designers, developers, and project managers frequently supplement their unique skills with a solid understanding of basic usability principles, but in most cases the information architect is still the one with the most experience and understanding of usability as it relates to web development.
Usability is and always has been a vital part of web site information architecture. This is shown in "the infamous three circles of information architecture," as described by Lou Rosenfeld and Peter Morville in the second edition of their book, Information Architecture for the World Wide Web, Users + Context + Content = IA. In other words, information architecture needs to take into account the information itself (content), the people using the information (users), and the business issues (context) in which the information is being presented.
In this case, usability acts as a subset of information architecture. Usability is certainly important, but other concerns need to be addressed as well. In the content sphere, the format of the content, metadata associated with it, and content owners and maintainers are just some of the things that need to be taken into consideration. Budget, technical constraints, business goals and internal politics come into play in the context sphere. A completely user-centered approach to information architecture is neither realistically possible nor appropriate. Information architects should be adept at designing appropriate solutions by understanding and addressing all three areas equally.
Putting it to Use
Information architecture is undoubtedly user-focused and is tied very closely with usability. Many information architects also have significant experience and interest in usability issues, and usability specialists are often adept at performing the duties normally expected of an information architect.
However, there are usability issues that are not related to information architecture, and aspects of information architecture that do not pertain to usability, and understanding these details will help to define the proper roles of a successful web development team.
Jeff Lash is a User Experience Designer in the Health Sciences division of Elsevier. He is a co-founder and Advisory Board member of the Asilomar Institute for Information Architecture (AIfIA) and has also written articles and tutorials for Boxes and Arrows and WebWord. His personal website is jefflash.com.