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Information Architecture tests: Card Sorting

As the name suggests, this type of test consists in having the participant rearrange some “cards” – representing categories and subcategories of information – in an order that makes sense to them. This helps the researcher understand how people are naturally inclined to group information, which can be used for creating mental models of the user. In web design, this is especially useful for grouping content into menus and submenus in a way that allows a visitor to easily find what they are looking for, by essentially letting the users design the menu themselves.

Open vs Closed Card Sorting

There are three different ways to set up a card sorting test: open card sorting, closed card sorting, or a hybrid approach.

Open Card Sorting

In an open card sorting task, you present the participant with a set of cards and give them complete freedom in terms of sorting and grouping: the participant can create as many categories as they wish and give them a name that makes sense to them.

For instance, let’s imagine you want to test how to design the menu for a pet store website. The store caters for several types of animals, which you write down in each card:











Betta fish

Guinea Pig

In an open card sorting test, participants Mark and Lisa are both asked to group the cards according to their own made up categories.

Mark’s open card sort:

House PetsFishMiceBirds
DogCatGoldfishBetta fishMouseHamsterGuinea PigCanaryParakeet

Lisa’s open card sort:

DogCatTurtleGoldfishBetta fishMouseHamsterGuinea PigRabbit

As you can see, the two came up with two equally valid ways of classifying pets, with a few minor differences: Mark thinks that the Dog and Cat cards belong to the same generic “house pet” category, while Lisa thinks they should each get their own. She also thinks that Turtle belongs together with the fish cards as they all describe “aquatic” pets, whereas Mark put Turtle in the same “reptile” category as Gecko. They also grouped Rabbit differently: either together with other rodents or separately from mouse-like pets. They can at least agree on the fact that Canary and Parakeet should both be under “birds”. Open card sorting is especially useful for co-designing an IA structure from scratch with the users, but may not be particularly suited for testing an existing IA, for which a closed card sorting setup may be better.

Closed Card Sorting

In a closed card sorting test, you ask the participant to sort the cards according to pre-established categories that you provide them. 

In our pet store example, you would be the one providing Mark and Lisa with the categories according to what you want to test. For instance, the current menu structure for the website could have the following sections: “Cats & Dogs”, “Aquarium Pets”, “Terrarium Pets” and “Small Pets”. You’d then want to ask Mark and Lisa to sort the previous card into these categories only. 

Mark’s closed card sort:

Cats & DogsAquarium PetsTerrarium PetsSmall Pets
DogCatGoldfishBetta FishTurtleGeckoMouseHamsterGuinea PigRabbitCanaryParakeet

Lisa’s closed card sort:

Cats & DogsAquarium PetsTerrarium PetsSmall Pets
CatDogGold FishBetta FishGeckoTurtleMouseHamsterGuinea PigRabbitCanaryParakeet

The closed card sorting allows you to identify “problematic” cards in your proposed structure. In this case, turtles could be seen as either an aquarium pet or a terrarium pet. Assuming the store caters for both aquatic turtles and box turtles (tortoises), it could be a good idea to split the Turtle category in two. It’s good practice when conducting a closed card sorting test to ask the participants directly about any difficulties or uncertainties, which in this case could highlight a wish for an extra category (e.g. “birds”). Overall, closed card sorting is a great way to assess an existing IA structure, but can be a bit limiting as the participants are biased into using arbitrary categories that may not entirely reflect their mental models.

Hybrid card sorting

Hybrid card sorting is a good compromise between the previous two setups. In this version, you both will provide the participants with predefined categories and allow them to freely create new ones. Using the same four categories as before, both Mark and Lisa would end up creating a new category “Birds”:

Cats & DogsAquarium PetsTerrarium PetsSmall Pets
DogCatGoldfishBetta Fish(Turtle)Gecko(Turtle)MouseHamsterGuinea PigRabbit

An hybrid approach is more difficult to analyse, due to the participants potentially coming up with very different answers – but it’s a great way to both (de)validate a proposed IA and to come up with alternative ideas for sorting and grouping information.

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