Learn about card sorting

What is card sorting?

Card sorting is a user research technique that can help you discover how people understand and categorize information. In a card sort, participants sort cards containing different items into groups. You can use the results of a card sort to figure out how to group and label the information on your website in a way that makes the most sense to your audience.

Card sorting has many applications. It’s as useful for figuring out how content should be grouped on a website or in an app as it is for figuring out how to arrange the items in a retail store.

You can also run a card sort in person, using physical cards, or remotely with online tools such as OptimalSort.

When you should use card sorting

It’s best to do a card sort when you want to answer a specific, information-related question. For example, maybe you need to add a new category for “fitness trackers” to your online electronics store. On the other hand, you may want to redesign how information is grouped together across your entire website.

In this case, card sorting is the perfect technique to find out where people would commonly expect to find a category on your website. You simply present them with a list of cards containing the names of other items and have users sort them into groups that make sense to them.

Card sorting is most useful when you’ve got the information you need to organize, but you’re just not sure exactly how to organize it.

While card sorting is typically used in the early stages of the design process, when there’s no fixed information architecture (IA), it’s also common to use the technique to make changes to a later IA down the line.

Types of card sorting

There’s more than one way to run a card sort. In fact, there are 3 distinct approaches: open, closed and hybrid. Here’s what they’re each used for and the types of results you’re likely to see.

Open card sort

It’s best to run an open card sort if you’re designing a new website or improving an existing one.

In an open card sort, participants are able to create their own groups for cards. They then give these groups names that make sense to them.

Open card sorts can help you to design the initial information architecture of a website by giving you insight into where people expect to find content. Of course, as participants can label groups themselves, you’ll also learn what people think your categories should be called.

Closed card sort

Closed card sorting helps you reduce the number of categories on your website (based on which ones are commonly ignored) and identifies misleading or unclear categories.

In a closed card sort, you define the groups. Participants then sort the cards into the groups you’ve created – they can’t create their own.

These types of card sorts are best suited for getting people to rank or prioritize information. For example “Important to unimportant”. They’re also useful for seeing if your category labels make sense.

Hybrid card sort

Hybrid card sorting is an effective way of getting ideas for grouping your information, but at the same time providing categories to get people started or inspire them.

In a hybrid card sort, you define the groups and also allow participants to create their own. It’s a mix of open and closed card sorts, meaning you’ll gain some insight as to whether your pre-defined labels make sense to people as well as allowing people to give their own input on labels.

This technique is useful if you already have a partial IA and want to see how participants might sort and label around your existing structure. It’s also a good option if you’re unsure of all the categories you’ve chosen in a closed sort.

Online and offline card sorting

You can host card sorts offline “in person” (whether in the same room or over a video call), or “unmoderated” using online tools.

Offline – Moderated, in-person

Running a card sort in person is a great way to gather qualitative results. By hosting participants in-person, you’ll gain insight into why they make certain decisions and how they feel about the task as they do it. The flipside of this approach is that it’s difficult to gather quantitative data with in-person card sorts given the number of people required for any sort of meaningful analysis (20-30 is a good number to aim for).

This approach is also quite expensive and time-consuming. Hosting individuals will generally incur costs (travel, gift cards etc) and create additional work for you as you’ll have to print cards out and prepare them.

Online – Unmoderated, remote

Online card sorts are ideal for gathering quantitative data. As you don’t need to physically host people, you can include as many participants as you want. They’re also significantly cheaper to run.

However, it can be difficult to understand why things happen with an online card sort. As the sessions aren’t moderated, it can be difficult to know how people interpreted different labels, or where they struggled.

Should you run an online or offline card sort?

It’s best to do both – if you can. Start by conducting several (1 to 5) in-person card sorts to get an understanding of how and why people sort your content. Then, follow up with an online card sort to gain some solid quantitative data. Some tools (like OptimalSort) allow you to print cards for in-person card sorts and then make use of the analysis features by scanning them into the app.

Card sorting and tree testing

Card sorting is one of the best ways to gather insights about the nature of content and how people think.

Of course, card sorting isn’t the only technique that is useful when designing an IA. While card sorting can help to show you which things should go together, you need to ensure that people can find what they’re looking for. This is where tree testing comes into play.

Tree testing is a technique for evaluating how easy it is to find topics on a website. It’s also commonly known as reverse card sorting and is the perfect technique to complement card sorting. After you’ve analyzed your card sorting results and transformed them into a draft IA, you can test these insights using a tree test. Using this technique, you task users with seeking as opposed to sorting. This technique aims to replicate the experience of using a website – without visual distractions.

In a tree test, you charge participants with navigating through a text-only version of your IA to find a result. You record every step they take – including every wrong turn and the time it takes them to complete the task. What you’re left with is a wealth of information which you can use to identify problems in your IA. For example, you may find that people constantly mistake one section of your IA for another, making their time to complete a task that much longer.

Unlike usability testing, tree testing only focuses on the IA of your website. It makes the process of developing an IA much faster, as you can easily make refinements and tweaks without needing to get bogged down in costly redesigns.

How to run a card sort

OptimalSort is our card sorting tool. Compared to traditional card sorting methods, OptimalSort cuts back the required preparation and analysis time.

If you want to find out how to run a card sort, we’ve put together a guide that covers everything you need to know, from setting up the cards to analyzing the results.

The guide also explains the differences between open, closed and hybrid card sorts, how you can choose the right technique for your particular project and how to effectively manage participants.

Looking for something else?

Card sorting 101

Learn how to run a Card sorting in our 101 guide

Learn more about our card sorting tool, OptimalSort.

Tool demos

Take our tools for a spin in one of our demos