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***** Introduction *****
Ambiguous organisational schemas and structures, like those used on the web, divide information into categories that defy exact definition - documents and information are grouped into intellectually meaningful ways. The foundation for a good architecture is a well-designed hierarchy.
Three main difficulties in informational hierarchy structure have been defined as:
1. Disorientation
It has been found that users often become lost within the structure of an application. The first difficulty is disorientation or the lost-in-hypertext problem, which arises from unfamiliarity with the structure or conceptual organization of the application. Here users have difficulty deciding which page to view next because they are unable to visualise where the information they are looking for could be. The decision concerning which page to view next first involves understanding one's current location within the site, then selecting the proper route. However, users may not even know their current location within a site/application.
A proper way to reduce this problem is to organize the application according to a users expectation of how the application should be organized. We are achieving this by conducting user interviews, task and goal analysis and designing the application around the needs of our users based on the results from these sessions.
2. The Embedded Digression Problem
The second difficulty is the embedded digression problem. This occurs when users pursue digressive paths within applications and lose their place or forget to return to their original document/page. This can be lessened by reducing the number of ad-hoc, or embedded links, in the text - by placing them instead at the end or on the side of the document. Ad-hoc links can also be disruptive, in that the user "may be inclined to examine a particular subject or subjects in detail without first getting an appreciation of the overall context".
It is generally found that people make fewer mistakes if the hierarchical structure of the site is broader rather than deeper. In fact, research has generally found that ideally all information should be placed within three hierarchical levels from the initial homepage of the site. Specifically, the more levels users have to take in order to get the information they want, the less chance they will find this information.
3. The Art Museum Problem
The third difficulty is the art museum problem. This refers to the lack of memory for the navigational details of a significant part of the application, because the user is overwhelmed by the sheer amount of information. For instance, as when a person visiting a museum cannot hope to remember the details of all the artwork because of their great number, a large number and variation of navigational information (such as the various pages that they have visited) may consequently overwhelm the user. This can often have the effect of reducing a person's recall of the pages that they have visited.
Reducing the amount of information presented at one time, and properly organizing the navigational structure of the site can lessen this. For example, in a study comparing three types of structures:
Researchers found that participants recalled more information with the mixed design. The pure hierarchical structure was found to be too restrictive, and the non linear design presented too much information at one time.
Thus, we should present only the amount of links that are necessary - superfluous links will increase the probability that the users will be confused and disoriented. Additional support for this conclusion can be derived from the Hick-Hyman law, which generally states that the greater the number of options, the longer it takes to find the appropriate one because of greater uncertainty.
