How to determine categorization for a large ecommerce catalogue

Question

I have an existing online catalogue of more than 300 services to provide improvement to. One of the common complaints anecdotally is around the current navigation, that the labeling isn't clear and users can't find what they're looking for.

What's a good approach to arriving at a user-centered IA with so many elements? My initial thought was to do a closed card sorting exercise, but 300-some elements strikes me as too much to ask a user to go through, no? Most other references I've read talked about no more than around 100.

• Should I take a random sample of 100 services? Maybe use different samples with different users to cover all 300 services at least once?
• Do I take just the most popular services? I'm afraid this will just reinforce a bias toward those services that are already easily discoverable.
• Do I manually select a sample of services are representative of different aspects of the catalogue? In doing that, don't I risk introducing my own biases into the process?
• Am I not looking at the right approach? Perhaps there is something better suited to large collections of information that would let me get top-level structure, and then look at card sorting for each high-level category (assuming they would be smaller, say 50 to 100 elements)?

Answer 1

There are a number of methods you could use in order to make sure the navigation works.

First you could do a tree test to make sure that you really are having a navigation problem since you say that you have just heard it.

You could also do a classic task-based usability study on the site design to be sure that it's no a interface problem.

You could do a open or closed card test as you say. Perhaps you could focus on one section that is important to you.

You could look at similar websites to steal their approach. What labeling system are they using?

Talk to a subject matter expert - how would he or she organize the services?

Answer 2

If you're having trouble defining the categories, maybe it's because they don't exist.

Categories are only useful when they will be obvious to the users of your site--in which case they would probably be obvious to you, as well.

Think of the grocery store. If you want lettuce, you know to head for produce. If you want ground beef, you know to go to the meat aisle. Things become really difficult, however, if you need something that doesn't fit obviously into any section of the store. For example, where would toothpicks be? It isn't clear, and different stores might put them in different places. You might wander the entire store before you find them.

If there aren't clear categories to the products you are selling, putting a lot of effort into categorizing them probably won't make things any more useful to the users.

Rather than mutually exclusive categories, why not use a tagging system? Unlike a physical store, a website is not constrained by the requirement that everything must be in a single place. Every item can be tagged with as many attributes as might be interesting to a customer. You aren't locked into one way of navigating your products, and it will be much more flexible as you learn more about what your customers are interested in.