Pattern 63: Context dependent search categories **
AKA:

You have created a SEARCH BOX (14) but the material on your site is capable of classification in ways that users will understand and want to exploit in their searches. You understand STRUCTURED MENUS (19).

How can you support sensible classification-based searches.

Therefore

Prefer free text searches to classified ones unless there is a well thought out, shared classification scheme. Include a ‘free text’ option among the other categories. Back up classified searches with full text searches. Make it visually clear if there are multiple places on the page from where a search may be initiated.

Make sure that there are visual cues indicating the presence of classification menus. Use radio buttons if there a few choices. Place these above or below the text box.

Ensure that CONTENT IS LINKED TO NAVIGATION (76).

Contributors and sources
Veen (2001)

On the HMV music site illustrated above it is not possible to search by record label – which is inconvenient if you are interested in an obscure genre supported by specialist labels. It is not immediately obvious whether or not one might get anything useful back by interpreting Artist as Composer if you were interested in the music of Sullivan, say. Sifting through a list of Gilbert O’Sullivan records probably isn’t what you had in mind. Therefore you might not bother and go off to Amazon where they do things differently – not necessarily better but differently. HMV have lost a punter. Amazon have the opposite problem in that only the category search is evident when you first look at the site (see Pattern 25). It takes a while to realize that you can also do category based searches.

So what’s wrong? We think that HMV haven’t thought enough about the use cases and their range of users. As a result they haven’t thought enough about the classification scheme. To be fair a later version of the site allows one to search by keyword which solves most of these problems. But this example does illustrate the risks associated with classification-based search and the need to get the classification structure right and makes sure it really covers the territory. Just for fun, see if you can add to the list of music categories listed below.

Artist, Catalogue number, Composer, Copyright owner, Date range composed, Date range performed, Label, Soloist, Song, Title, Work.

Amazon need to make it clearer that there is more than one entry point to searches.

Using category based searches addresses the need to speed up searches but is not good for finding specific, but unpredictable, content unless the category model is complete and shared by the user. A site concerning zoological types could expect this to be the case and we think that it is possible for music and book sites. For other domains there may be no shared classification model.

Another problem with the classified search approach is that users often ignore pulldown menus or text boxes because they don’t always realize that there are options other than the default that is displayed.

If space permits and there are few options then radio buttons may be better. Place these above or below the text box to save space and indicate conceptual proximity by spatial proximity. If they are at the side users may not chunk them with the search box.

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