Illustration showing 3 people in front of a table with a pile of index cards on top of it

Card Sorting: How To Get Started

by Molly Fitz-Patrick | | 29 min read

It’s likely you’ve come across the concept of card sorting, whether or not you’re in UX. The popular, low-tech research technique is used to organize data sets. It’s especially useful for information architecture, menu structures, workflows and website navigation. While it’s easy enough to run a card sort, there’s a massive difference between a flop and a success. Let’s dive into the do’s and don’ts so that you can start card sorting successfully.

What Is Card Sorting? 

Card sorting is a user research technique in which the researcher asks a group of people to sort a batch of index cards (physical or digital), that represents a set of content, into categories. 

Participants are also asked to describe the reasons behind their groupings so that we can understand how they think. 

Design Consultant Donna Spencer provides an excellent example of a card sort in her IxDF Master Class, “How To Use Card Sorting For Better Information Architecture”.

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How To Use Card Sorting 

Card sorting helps us understand the way people think so that we can arrange content in a way that makes sense to them. 

The results of a card sort can be abstract because we will learn about concepts, ideas and the way people think about particular subjects and issues instead of how to create a perfect hierarchy for Information Architecture (IA) or a website’s navigation. A card sort can reveal how a person’s, or group of people’s, background and personal experience has affected the way they think

Through a successful card sort, you will also learn the following: 

  • What goes together and why

  • Different ideas and methods of organizing content 

  • If people think similarly or differently

While card sorting is more often used to create IAs, website navigation and menu structures, it can also be used for internal communication and politics. 

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In this clip, Donna Spencer explains one of the less obvious uses of card sorting, and what it can tell us.

How Not To Use Card Sorting

Although card sorting is an effective tool in enhancing your IA, don’t expect it to create it for you. Card sorting is qualitative and exploratory, so the results can be inconsistent – not a great basis to make an IA from scratch. Similarly, it can’t tell you whether your IA works. Even though the card sort will inform your IA, you won’t know if it’s good or not. Donna Spencer suggests a tree test instead. 

In addition, card sorting is not good for these: 

  • Definitive, black and white answers

  • Quantitative, statistically valid data

How To Run a Card Sort

There are several things you need to consider before you start card sorting. Think about them carefully because they will affect the outcome of the exercise. 

Set Objectives

As with any research methodology, you must clearly establish what you want to learn. Next, think about whether card sorting is the best way to learn it. 

Tools 

Naturally, you’ll need some cards. Plain index cards or Post-it notes work well for an in-person card sort. You can use anywhere from a handful up to about 100 (sometimes more, depending on the project). For a virtual card sort, however, try to limit the number of cards to 50. 

An image shows a pair of hands arranging a set of different coloured post it notes, in the manner of a card sort
Index cards or Post-it notes work well for card sorting.
© UX Indonesia, Unsplash License

You can find several card sorting tools online, such as OptimalSort, but applications like Trello, Miro or GitHub can work well too. One of the main benefits of using a card sorting tool is that it’s already on the computer, ready for analysis and you don’t have to go through the laborious process of transferring your results from cards to spreadsheet. 

Instructions & Preparation

Before your card sort begins, whether physically or digitally, you must prepare your instructions. These must be clear so your participants know what to do. Good instructions are particularly important for an online card sort.

Think about the questions people may ask and if you’re conducting your card sort online – include the answers to those questions in your instructions. For an in-person card sort, prepare your answers in advance. 

Participants may ask questions like: 

  • This card fits with more than one group; can I put it in more than one place? 

  • I don’t understand this card; can I exclude it? 

  • There seems to be some content missing; can I add a card? 

Another important factor to consider before you start is your analysis. Think about the optimal amount of results you want; you may want only 5 people in your sample or as many as 25. If you’re doing an in-person card sort, figure out how you’ll get your data from the physical world into the digital.  

Content

Your content is one of the most, if not the most, critical parts of card sorting. Your results will come entirely from the content you give to your participants, so it must be evaluated thoroughly.

Donna Spencer describes some of the elements, and their significance, of your card sorting content:

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If you’ve got a particularly large content set, it may be wise to split them up into several card sorts to get the results you want. 

Steer clear of jargon. If people can’t understand your content, they won’t be able to group the cards effectively, which will negatively affect your results. People tend to force associations and make connections that aren’t there when they don’t fully grasp the information presented to them. Ensure that your content is clear and direct to get the best possible outcome.

People

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The people you select for your card sort are really important; Donna Spencer explains what you need to consider. 

You may wonder what the optimal number of people to have for your card sort is. Generally, this is easier to manage for an in-person card sort as you’re limited by space and time. However, with an online card sort you may be tempted to send it out to everyone in your contact list. Try to avoid this. Hundreds of responses can make for overwhelming analysis. Instead, send your card sorting exercise to a small group of people and see what comes back. It gives you the opportunity to revise and adapt your card sort, and you can always send it to more people if necessary.  

Facilitate

Start with an introduction, give your participants a bit of context and go through the instructions. In a physical card sort, you can simply speak to your participants, and if you choose to do it remotely via Zoom or something similar, but for most virtual cart sorts done through a tool, this will have to be written out. 

Don’t keep explaining or overhelp. It’s likely that one or some of your participants may look to you for guidance; you can repeat the instructions, but don’t go into more detail. You’ll get better results if they carry on without further assistance. 

It’s better to not tell the people in your card sort that they’ll be labeling the groups they create. Unfortunately, this can’t be done in a virtual card sort with an online tool. Language and labels will influence the categories – your participants will think more about the categories themselves, rather than the content that goes into them. You’ll lose the fluidity of the card sorting process.

During the card sort, take notes and listen to what your participants are saying. Try not to hover as this can hinder the organic conversation between the participants.

Incentive

Like with any research activity, incentivizing your participants can be really valuable and mean the difference between them participating or not. This is especially true of online card sorts.

Analysis

As mentioned, analysis will probably be easier with an online card sort as your results are already plugged into your computer. While this is not the case with an in-person card sort, you can use numbers and a spreadsheet to make your life easier. Number each card and put it into your spreadsheet along with the card’s content; then all you have to do is input the numbers.

First you want to get an overview. Donna Spencer shares how you do this: 

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Then go more in-depth, start to compare participants in detail and see what was similar and different in their results. And look at what insights you can pull from the variations you find. For an IA, did they all make an “About Us” section? If so, what cards did they put into that group? Sometimes people will create the same groupings, but put different cards into the groupings. You can also look at specific cards, and see where each person put them. 

Remember this is a qualitative research exercise, so you’re trying to gain insights. You want to discover what’s interesting or what stands out in your results. Review your objectives and what you wanted to learn from the card sort.

Finally, apply your findings to your project. It’s best to combine them with other research methods. 

The Take Away

Card Sorting is an effective technique to learn about how your users think. This research method can provide useful insights that will benefit the project you’re using it for. There are a few important factors to consider in running your own card sort, such as your objectives, tools, content and people. It’s a straightforward process, but it’s crucial that you do it properly and pay close attention to each element. The insights you gain from card sorting can be invaluable, but don’t expect unequivocal results. In short, card sorting is a powerful tool that’s low cost, low effort and low tech – make it one of your go-to research techniques! 

References and Where to Learn More  

Dive deeper into card sorting with Donna Spencer’s Master Class: “How To Use Card Sorting For Better Information Architecture”: https://www.interaction-design.org/master-classes/how-to-use-card-sorting-for-better-information-architecture 

How to run card sorts and what tools to use:
https://digital.gov/2022/01/06/open-source-information-architecture-design-using-the-tools-you-have-to-conduct-card-sorting-and-tree-testing/ 

https://www.usability.gov/how-to-and-tools/methods/card-sorting.html  

How to screen participants for your card sort: 
https://www.interaction-design.org/literature/article/how-to-screen-research-participants

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