I got to thinking about this question actually at the supermarket recently. I was looking for an item that I thought just had to be in the baking section ... because that's how brick-and-mortar stores are organized at the top-level, by type or category ... when in actuality this one item was an exception in that it was shelved with all the products of the same brand.
Are there examples related to information architecture where mixing classification schemes like this is appropriate or effective? A search led me to this article by Donna Spencer, in which she runs down various schemes (e.g. alphabetical, by task, by subject, etc.) and concludes:
In reality you can use a combination; you could:
- Mix up types at each level
- Start with one type and use a different type at the next level
- Use more than one approach for your whole content set
It's not unusual to see schemes that vary by level, but what about that first bullet point? I'm hard pressed to think of an IA that suddenly switches classification and then switches back between exceptions. That'd be a navigation experience without any consistency.
Mixing schemes within hierarchy levels just seems like a flat-out bad idea. No?