While shopping at Safeway for the Hunger Challenge, I couldn’t find the canned tomatoes. After several minutes of walking up and down the aisled marked both ‘Canned Fruit’ and ‘Canned Vegetables’ I felt like giving up on Pasta Fagioli. What is a tomato if it is neither a canned fruit nor a canned vegetable?

Turns out a tomato is Italian food. The canned tomatoes of all varieties, from whole to petite diced, were shelved alongside pre-made pasta sauces.

At first I felt sort of silly. “Of course!” I thought, tomatoes are a natural pairing for the pastas in that aisle. But later on I realized that my first inclination had been correct. I’d looked for tomatoes by a categorization that considered the product’s definition, not its use. Why? Because no other non-prepared fruit or vegetable in the store was categorized by use.

The same things happens when websites are designed around categories that limit interpretation.

How to fix this in both supermarkets and websites?

Make categories that follow a common convention. On Safeway.com this means grouping all items that fall into a form factor:

Use card sorting tools. Feeling too familiar with your products? Do a card sort to group items. One major issue to watch out for: keyword bias. Jakob Nielsen has a lengthy (but useful) Alertbox on doing so.

Observe people. Look at what people are buying and how they buy it. Baking items are included together because they’re all used together, and that grouping can prompt a shopper to pick up another item (like chocolate chips) when really he just needed more flour.

Gather data. Then use it. On the Internet we have have an easy time gathering data, but often spend very little time putting that data to use. Take a look at your on-site search queries; they’re a huge clue into what people can’t find on your website. At a physical store it means that your employees report what questions customers asked. Sure, it can be a time consuming effort, but the rewards are likely enormous. Three years later, Avinash Kaushik’s advice on on-site search analysis still holds true. Two days after I posted this, A List Apart published Avinash Kaushik’s most recent advice on on-site search analytics.

Do the best with what you have. On the Internet, the Safeway folks can include as many items as they want in the canned foods section. In a supermarket there are physical limitations to the number of items you can include on an aisle. Thus, if you’re dealing with an usual or makeshifted category structure, give people help. Aisle signs are a good start.