On our current website, we have 3 organizational schemes in play: audience, topical and task. These are implemented in 3 sections of navigation, with each navigation devoted to a scheme and on distinct areas of the page. This was setup based on recommendations from the book "Information Architecture for the World Wide Web", Rosenfeld & Morville. In the text, they explicitly say "the power of a pure organization scheme derives from its ability to suggest a simple mental model for users to quickly understand. Users easily recognize an audience-specific or topical organization. However, when you start blending elements of multiple schemes, confusion is almost guaranteed. "
In a redesign project, there is significant pressure to create navigation that mixes these schemes. There are plenty of examples of sites that do this. My response, of course, is that just because others are doing it doesn't make it correct.
My question: is there any new evidence that mixing organizational schemes in a single navigation structure is no longer confusing to users? Is it ok to mix schemes, perhaps as long as it's limited....say adding only 1 audience link to an otherwise topical grouping?
If you can point me to any recent studies about this topic, I would be grateful. If you otherwise want to weigh in with your thoughts, that would also be most appreciated. The IA text is copyright 1998...maybe this is no longer applicable in the WWW or 2013???