A matrix structure, as Jesse James Garrett describes it, lets users move through content along two or more dimensions, horizontally, vertically, and in a three-dimensional matrix, laterally as well. Garrett cautions that using more than three dimensions for a primary navigation system creates real usability problems. A matrix serves a purpose similar to a database with faceted metadata: it lets people view the same content from different perspectives, and when each dimension serves a different audience's need, a matrix can create genuinely useful, audience-focused points of entry.
Most large digital information spaces don't rely on a single structural pattern at all, they combine several into a hybrid structure. A hierarchy typically provides the overarching structure, a database pattern often organizes a homogeneous subset of the content, hypertext links weave in cross-references throughout, and a linear sequence might guide users through a specific tour or process. Combining patterns lets a single information space accommodate genuinely different types of content and user needs within one coherent whole.
A hybrid structure isn't a compromise or a failure to choose, for anything beyond a small, simple site: it's usually the only honest answer.
Correct: a hierarchy as the overarching structure, combined with a database for the course catalog, and a matrix for multi-audience content. A site of this scope and heterogeneity is a textbook case for a hybrid structure. A single pattern applied uniformly, a pure hierarchy, pure hypertext, or a single linear sequence, cannot reasonably serve admissions information, a structured course catalog, research publications, and administrative services all at once. Each of those content types has different structural needs.
The course catalog is a strong candidate for a matrix structure specifically, since it plausibly needs to serve at least two distinct audience dimensions, for example, a prospective student browsing courses by subject of personal interest, and a current student checking which courses satisfy a specific degree requirement. Structuring the catalog as a matrix lets both audiences view the same underlying course data along whichever dimension matches their need, without maintaining two separate copies of the catalog.Even here, Garrett's caution still applies: it would be tempting to add a third or fourth dimension, say, by instructor or by semester, but the source material is explicit that more than three dimensions in a primary navigation system creates real usability problems. Two clear, well-chosen dimensions usually serve people better than four dimensions that overwhelm them with combinations.