11 February 2006
Topical schemes sort categories based on what they're about, like the organization of a textbook (simple to complicated). Task-oriented schemes are organized in "doing" order, such as the steps one takes to make a sandwich. Audience-oriented schemes separate items according to who wants them, like the split between members and nonmembers, or the MPAA categories for movie age appropriateness (e.g., PG-13).
Consider how you might organize the steps involved of visiting a website. In task order they would appear as (1) turn on computer, (2) open the browser, (3) type in the website address, (4) read the page, (5) close the browser, and (6) turn off the computer. In topic order, the "turn on" and "turn off" items would be combined, since people pair these together; same with "open the browser" and "close the browser." In alphabetical order, on the other hand, the browser is closed before it's opened, and the computer is turned off before it's turned on. Using alphabetical order is pretty stupid here would be pretty stupid, eh? (Did you ever wonder notice that the options under the File menu aren't alphabetized?)
The problem with ambiguous systems, of course, is that people don't necessary categorize things in the same way. In fact, this is why people can't find things in other people's kitchens! (See my post from 7 Feb.) We don't put measuring spoons, soup spoons, and serving ladles in the same drawer, even though they're all spoons. Instead, we interpret categories according to how we perceive these connections, subjectively.
Think about how restaurant menus are organized. First they are organized in task order: appetizers in the front, entrees in the middle, and desserts near the back. Then they might be organized by ingredient (e.g., all the pasta dishes appear together), although it's unclear in what order these ingredients are listed. And within these categories, what's the order? Maybe it's profitability; maybe it's to show off the chef's skills or the breadth of available selections; maybe it's to put the most popular or intruiguing items at the top.
By the way, in my opinion audience-oriented categorization is the most powerful and useful of all sorting techniques, and yet it's woefully underutilized. Organizing items by popularity is simply a variation on this idea.
As soon as you start really looking at how people use information, you will run away from exact schemes almost immediately, as much as possible. (Long flat lists, like the entries in an index, still demand some sort of umbrella sorting. Short lists, like the options in a computer menu, are fair game. Have you ever noticed that the choices under the File menu are generally in task order?)
Nothing in life is exact, so why do we force it?