Section 9.10. Faceted Classification
9.10. Faceted ClassificationIn the 1930s, an Indian librarian by the name of S. R. Ranganathan created a new type of classification system. Recognizing the problems and limitations of these top-down single-taxonomy solutions, Ranganathan built his system upon the notion that documents and objects have multiple dimensions, or facets. The old model asks the question, "Where do I put this?" It's more closely tied to our experience in the physical world, with the idea of one place for each item. In contrast, the faceted approach asks the question, "How can I describe this?" Like many librarians, Ranganathan was an idealist. He argued that you must build multiple "pure" taxonomies, using one principle of division at a time. He suggested five universal facets to be used for organizing everything:
In our experience, the faceted approach has great value, but we don't tend to use Ranganathan's universal facets. Instead, common facets in the business world include:
Still confused about facets? See Figure 9-27. All we're really doing is applying the structure of a fielded database to the more heterogeneous mix of documents and applications in a web site. Rather than the one-taxonomy-fits-all approach of Yahoo!, we're embracing the concept of multiple taxonomies that focus on different dimensions of the content. Figure 9-27. Single hierarchy versus multiple (faceted) hierarchies Wine.com provides a simple example of faceted classification. Wine has several facets that we commonly mix and match in our selection process at restaurants and grocery stores:
Note that some facets are flat lists (e.g., price) whereas some must be represented hierarchically (e.g., type). When we look for a moderately priced Californian Merlot, we're unconsciously defining and combining facets. Wine.com leverages a faceted classification to enable this experience online. The main shopping page in Figure 9-28 presents three ways to browse, providing multiple paths to the same information. Figure 9-28. Faceted classification at Wine.com The Power Search, shown in Figure 9-29, provides the ability to combine facets into the rich type of query we usually express in natural language. Figure 9-29. Power Search at Wine.com The results page (Figure 9-30) has our list of moderately priced Californian Merlot wines. Note that we're not only able to leverage facets in the search, but we can also use the facets to sort results. Wine.com has added ratings from several magazines (WE = Wine Enthusiast, WS = Wine Spectator) as yet another facet. Figure 9-30. Flexible search and results display The information architects and designers at Wine.com have made decisions throughout the site about how and when to leverage facets within the interface. For example, you can't browse by price or rating from the main page. Hopefully, these are informed decisions made by balancing an understanding of user needs (how people want to browse and search) and business needs (how eVineyard can maximize sales of high-margin items). The nice thing about a faceted classification approach is that it provides great power and flexibility. With the underlying descriptive metadata and structure in place, information architects and interface designers can experiment with hundreds of ways to present navigation options. The interface can be tested and refined over time, while the faceted classification provides an enduring foundation. In recent years, search solutions built atop faceted classifications have really come into their own, thanks in part to search vendor Endeca and its "Guided Navigation" model (Figures 9-31 and 9-32), which encourages users to refine or narrow their searches based on metadata fields and values. Figure 9-31. Guided navigation at Ace Hardware Guided navigation was quickly embraced in the online retail arena, where there's a clear link between findability and profitability. More recently, this hybrid search/browse model has been widely adopted across industry, government, healthcare, publishing, and education. As Figure 9-32 shows, guided navigation is even being used to improve library catalogs. Ranganathan would be proud. Figure 9-32. Guided navigation at NCSU In addition to the increasing mainstream implementation of controlled vocabularies, we're also enjoying a growing wealth of resources to support these efforts. Here are just a few:
Metadata, controlled vocabularies, and thesauri are increasingly becoming the building blocks of most major web sites and intranets. Single-taxonomy solutions are giving way to more flexible, faceted approaches. Put simply, if you're an information architect, we see facets in your future![§]
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EAN: 2147483647
Pages: 194