August 15, 2022
2 min

Card Sorting vs Tree Testing: what's the best?

A great information architecture (IA) is essential for a great user experience (UX). And testing your website or app’s information architecture is necessary to get it right.

Card sorting and tree testing are the very best UX research methods for exactly this. But the big question is always: which one should you use, and when? Very possibly you need both. Let’s find out with this quick summary.

What is card sorting and tree testing? 🧐

Card sorting is used to test the information architecture of a website or app. Participants group individual labels (cards) into different categories according to  criteria that makes best sense to them. Each label represents an item that needs to be categorized. The results provide deep insights to guide decisions needed to create an intuitive navigation, comprehensive labeling and content that is organized in a user-friendly way.

Tree testing is also used to test the information architecture of a website or app. When using tree testing participants are presented with a site structure and a set of tasks they need to complete. The goal for participants is to find their way through the site and complete their task. The test shows whether the structure of your website corresponds to what users expect and how easily (or not) they can navigate and complete their tasks.

What are the differences? 🂱 👉🌴

Card sorting is a UX research method which helps to gather insights about your content categorization. It focuses on creating an information architecture that responds intuitively to the users’ expectations. Things like which items go best together, the best options for labeling, what categories users expect to find on each menu.

Doing a simple card sort can give you all those pieces of information and so much more. You start understanding your user’s thoughts and expectations. Gathering enough insights and information to enable you to develop several information architecture options.

Tree testing is a UX research method that is almost a card sort in reverse. Tree testing is used to evaluate an information architecture structure and simply allows you to see what works and what doesn’t. 

Using tree testing will provide insights around whether your information architecture is intuitive to navigate, the labels easy to follow and ultimately if your items are categorized in a place that makes sense. Conversely it will also show where your users get lost and how.

What method should you use? 🤷

You’ve got this far and fine-tuning your information architecture should be a priority. An intuitive IA is an integral component of a user-friendly product. Creating a product that is usable and an experience users will come back for.

If you are still wondering which method you should use - tree testing or card sorting. The answer is pretty simple - use both.

Just like many great things, these methods work best together. They complement each other, allowing you to get much deeper insights and a rounded view of how your IA performs and where to make improvements than when used separately. We cover more reasons why card sorting loves tree testing in our article which dives deeper into why to use both.

Ok, I'm using both, but which comes first? 🐓🥚

Wanting full, rounded insights into your information architecture is great. And we know that tree testing and card sorting work well together. But is there an order you should do the testing in? It really depends on the particular context of your research - what you’re trying to achieve and your situation. 

Tree testing is a great tool to use when you have a product that is already up and running. By running a tree test first you can quickly establish where there may be issues, or snags. Places where users get caught and need help. From there you can try and solve potential issues by moving on to a card sort. 

Card sorting is a super useful method that can be instigated at any stage of the design process, from planning to development and beyond.  As long as there is an IA structure that can be tested again. Testing against an already existing website navigation can be informative. Or testing a reorganization of items (new or existing) can ensure the organization can align with what users expect.

However, when you decide to implement both of the methods in your research, where possible, tree testing should come before card sorting. If you want a little more on the issue have a read of our article here.

Check out our OptimalSort and Treejack tools - we can help you with your research and the best way forward. Wherever you might be in the process.

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1 min read

Behind the scenes of UX work on Trade Me's CRM system

We love getting stuck into scary, hairy problems to make things better here at Trade Me. One challenge for us in particular is how best to navigate customer reaction to any change we make to the site, the app, the terms and conditions, and so on. Our customers are passionate both about the service we provide — an online auction and marketplace — and its place in their lives, and are rightly forthcoming when they're displeased or frustrated. We therefore rely on our Customer Service (CS) team to give customers a voice, and to respond with patience and skill to customer problems ranging from incorrectly listed items to reports of abusive behavior.

The CS team uses a Customer Relationship Management (CRM) system, Trade Me Admin, to monitor support requests and manage customer accounts. As the spectrum of Trade Me's services and the complexity of the public website have grown rapidly, the CRM system has, to be blunt, been updated in ways which have not always been the prettiest. Links for new tools and reports have simply been added to existing pages, and old tools for services we no longer operate have not always been removed. Thus, our latest focus has been to improve the user experience of the CRM system for our CS team.

And though on the surface it looks like we're working on a product with only 90 internal users, our changes will have flow on effects to tens of thousands of our members at any given time (from a total number of around 3.6 million members).

The challenges of designing customer service systems

We face unique challenges designing customer service systems. Robert Schumacher from GfK summarizes these problems well. I’ve paraphrased him here and added an issue of my own:

1. Customer service centres are high volume environments — Our CS team has thousands of customer interactions every day, and and each team member travels similar paths in the CRM system.

2. Wrong turns are amplified — With so many similar interactions, a system change that adds a minute more to processing customer queries could slow down the whole team and result in delays for customers.

3. Two people relying on the same system — When the CS team takes a phone call from a customer, the CRM system is serving both people: the CS person who is interacting with it, and the caller who directs the interaction. Trouble is, the caller can't see the paths the system is forcing the CS person to take. For example, in a previous job a client’s CS team would always ask callers two or three extra security questions — not to confirm identites, but to cover up the delay between answering the call and the right page loading in the system.

4. Desktop clutter — As a result of the plethora of tools and reports and systems, the desktop of the average CS team member is crowded with open windows and tabs. They have to remember where things are and also how to interact with the different tools and reports, all of which may have been created independently (ie. work differently). This presents quite the cognitive load.

5. CS team members are expert users — They use the system every day, and will all have their own techniques for interacting with it quickly and accurately. They've also probably come up with their own solutions to system problems, which they might be very comfortable with. As Schumacher says, 'A critical mistake is to discount the expert and design for the novice. In contact centers, novices become experts very quickly.'

6. Co-design is risky — Co-design workshops, where the users become the designers,  are all the rage, and are usually pretty effective at getting great ideas quickly into systems. But expert users almost always end up regurgitating the system they're familiar with, as they've been trained by repeated use of systems to think in fixed ways.

7. Training is expensive — Complex systems require more training so if your call centre has high churn (ours doesn’t – most staff stick around for years) then you’ll be spending a lot of money. …and the one I’ve added:

8. Powerful does not mean easy to learn — The ‘it must be easy to use and intuitive’ design rationale is often the cause of badly designed CRM systems. Designers mistakenly design something simple when they should be designing something powerful. Powerful is complicated, dense, and often less easy to learn, but once mastered lets staff really motor.

Our project focus

Our improvement of Trade Me Admin is focused on fixing the shattered IA and restructuring the key pages to make them perform even better, bringing them into a new code framework. We're not redesigning the reports, tools, code or even the interaction for most of the reports, as this will be many years of effort. Watching our own staff use Trade Me Admin is like watching someone juggling six or seven things.

The system requires them to visit multiple pages, hold multiple facts in their head, pattern and problem-match across those pages, and follow their professional intuition to get to the heart of a problem. Where the system works well is on some key, densely detailed hub pages. Where it works badly, staff have to navigate click farms with arbitrary link names, have to type across the URL to get to hidden reports, and generally expend more effort on finding the answer than on comprehending the answer.

Groundwork

The first thing that we did was to sit with CS and watch them work and get to know the common actions they perform. The random nature of the IA and the plethora of dead links and superseded reports became apparent. We surveyed teams, providing them with screen printouts and three highlighter pens to colour things as green (use heaps), orange (use sometimes) and red (never use). From this, we were able to immediately remove a lot of noise from the new IA. We also saw that specific teams used certain links but that everyone used a core set. Initially focussing on the core set, we set about understanding the tasks under those links.

The complexity of the job soon became apparent – with a complex system like Trade Me Admin, it is possible to do the same thing in many different ways. Most CRM systems are complex and detailed enough for there to be more than one way to achieve the same end and often, it’s not possible to get a definitive answer, only possible to ‘build a picture’. There’s no one-to-one mapping of task to link. Links were also often arbitrarily named: ‘SQL Lookup’ being an example. The highly-trained user base are dependent on muscle memory in finding these links. This meant that when asked something like: “What and where is the policing enquiry function?”, many couldn’t tell us what or where it was, but when they needed the report it contained they found it straight away.

Sort of difficult

Therefore, it came as little surprise that staff found the subsequent card sort task quite hard. We renamed the links to better describe their associated actions, and of course, they weren't in the same location as in Trade Me Admin. So instead of taking the predicted 20 minutes, the sort was taking upwards of 40 minutes. Not great when staff are supposed to be answering customer enquiries!

We noticed some strong trends in the results, with links clustering around some of the key pages and tasks (like 'member', 'listing', 'review member financials', and so on). The results also confirmed something that we had observed — that there is a strong split between two types of information: emails/tickets/notes and member info/listing info/reports.

We built and tested two IAs

pietree results tree testing

After card sorting, we created two new IAs, and then customized one of the IAs for each of the three CS teams, giving us IAs to test. Each team was then asked to complete two tree tests, with 50% doing one first and 50% doing the other first. At first glance, the results of the tree test were okay — around 61% — but 'Could try harder'. We saw very little overall difference between the success of the two structures, but definitely some differences in task success. And we also came across an interesting quirk in the results.

Closer analysis of the pie charts with an expert in Trade Me Admin showed that some ‘wrong’ answers would give part of the picture required. In some cases so much so that I reclassified answers as ‘correct’ as they were more right than wrong. Typically, in a real world situation, staff might check several reports in order to build a picture. This ambiguous nature is hard to replicate in a tree test which wants definitive yes or no answers. Keeping the tasks both simple to follow and comprehensive proved harder than we expected.

For example, we set a task that asked participants to investigate whether two customers had been bidding on each other's auctions. When we looked at the pietree (see screenshot below), we noticed some participants had clicked on 'Search Members', thinking they needed to locate the customer accounts, when the task had presumed that the customers had already been found. This is a useful insight into writing more comprehensive tasks that we can take with us into our next tests.  

What’s clear from analysis is that although it’s possible to provide definitive answers for a typical site’s IAs, for a CRM like Trade Me Admin this is a lot harder. Devising and testing the structure of a CRM has proved a challenge for our highly trained audience, who are used to the current system and naturally find it difficult to see and do things differently. Once we had reclassified some of the answers as ‘correct’ one of the two trees was a clear winner — it had gone from 61% to 69%. The other tree had only improved slightly, from 61% to 63%.

There were still elements with it that were performing sub-optimally in our winning structure, though. Generally, the problems were to do with labelling, where, in some cases, we had attempted to disambiguate those ‘SQL lookup’-type labels but in the process, confused the team. We were left with the dilemma of whether to go with the new labels and make the system initially harder to use for staff but easier to learn for new staff, or stick with the old labels, which are harder to learn. My view is that any new system is going to see an initial performance dip, so we might as well change the labels now and make it better.

The importance of carefully structuring questions in a tree test has been highlighted, particularly in light of the ‘start anywhere/go anywhere’ nature of a CRM. The diffuse but powerful nature of a CRM means that careful consideration of tree test answer options needs to be made, in order to decide ‘how close to 100% correct answer’ you want to get.

Development work has begun so watch this space

It's great to see that our research is influencing the next stage of the CRM system, and we're looking forward to seeing it go live. Of course, our work isn't over— and nor would we want it to be! Alongside the redevelopment of the IA, I've been redesigning the key pages from Trade Me Admin, and continuing to conduct user research, including first click testing using Chalkmark.

This project has been governed by a steadily developing set of design principles, focused on complex CRM systems and the specific needs of their audience. Two of these principles are to reduce navigation and to design for experts, not novices, which means creating dense, detailed pages. It's intense, complex, and rewarding design work, and we'll be exploring this exciting space in more depth in upcoming posts.

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1 min read

First click testing data: Correct first click lead to 3X higher task success

In 2009, Bob Bailey and Cari Wolfson published published findings that changed how we approach first click testing and usability testing. They analyzed 12 scenario-based user tests and found that if someone gets their first click right, they're about twice as likely to complete their task successfully. This finding was so compelling that we built First Click Testing (formerly Chalkmark) specifically to help teams test this.  But we'd never actually validated their research using our own data, until now.

Turns out, we're sitting on one of the world's largest databases of tree testing results. So we analyzed millions of task responses to see if the "first click predicts success" hypothesis holds up.

It does. Convincingly.

Users who get their first click correct are nearly three times more likely to complete their task successfully (70% vs 24% success rate).

Here's how we validated the original study, what our data shows, and why first clicks matter more than you might think.

Original first click testing study: 87% task success rate

Bob and Cari analyzed data from twelve usability studies on websites and products with varying amounts and types of content, a range of subject matter complexity, and distinct user interfaces. They found that people were about twice as likely to complete a task successfully if they got their first click right, than if they got it wrong:

If the first click was correct, the chances of getting the entire scenario correct was 87% if the first click was incorrect, the chances of eventually getting the scenario correct was only 46%.

Our Tree Testing data: First clicks predict 70% task success rate

We analyzed millions of tree testing responses in our database. We've found that people who get the first click correct are almost three times as likely to complete a task successfully:

If the first click was correct, the chances of getting the entire scenario correct was 70% if the first click was incorrect, the chances of eventually getting the scenario correct was 24%

To give you another perspective on the same data, here's the inverse:

If the first click was correct, the chances of getting the entire scenario incorrect was 30% if the first click was incorrect, the chances of getting the whole scenario incorrect was 76%

How Tree Testing measures first click success and task completion

Bob and Cari proved the usefulness of the methodology by linking two key metrics in scenario-based usability studies: first clicks and task success. First Click Testing doesn't measure task success — it's up to the researcher to determine as they're setting up the study what constitutes 'success', and then to interpret the results accordingly. Tree Testing (formerly Treejack) does measure task success — and first clicks.

In a tree test, participants are asked to complete a task by clicking though a text-only version of a website hierarchy, and then clicking 'I'd find it here' when they've chosen an answer. Each task in a tree test has a pre-determined correct answer — as was the case in Bob and Cari's usability studies — and every click is recorded, so we can see participant paths in detail.

Thus, every single time a person completes an individual tree testing task, we record both their first click and whether they are successful or not. When we came to test the 'correct first click leads to task success' hypothesis, we could therefore mine data from millions of task.

To illustrate this, have a look at the results for one task. The overall Task result, you see a score for success and directness, and a breakdown of whether each Success, Fail, or Skip was direct (they went straight to an answer), or indirect (they went back up the tree before they selected an answer):

Tree testing task results showing success and directness scores

In the pie tree for the same task, you can look in more detail at how many people went the wrong way from a label (each label representing one page of your website):

Pie tree visualization showing first click paths in tree testing

In the First Click tab, you get a percentage breakdown of which label people clicked first to complete the task:

First click data breakdown by label in tree testing

And in the Paths tab, you can view individual participant paths in detail (including first clicks), and can filter the table by direct and indirect success, fails, and skips (this table is only displaying direct success and direct fail paths):

Participant path analysis showing direct success and fail rates

How to run first click tests: Best practices for usability testing

First click analysis is one of the most predictive metrics in usability testing. Whether you're testing wireframes, landing pages, or information architecture, measuring first click success gives you early insight into whether your design will work.

This analysis reinforces something we already knew: first clicks matterIt is worth your time to get that first impression right. You have plenty of options for measuring the link between first clicks and task success in your scenario-based usability tests. From simply noting where your participants go during observations, to gathering quantitative first click data via online tools, you'll win either way. And if you want quantitative first click data, Optimal has you covered. First Click Testing works for wireframes and landing pages, while Tree Testing validates your information architecture.

To finish, here are a few invaluable insights from other researchers on getting the most from first click testing:

About this study

This analysis was conducted in 2015 using millions of task responses from Optimal’s First Click and Tree Testing tools. While the dataset predates recent UI trends, the underlying behavioral principle, that a correct first click strongly predicts task success, remains consistent with modern usability research.

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1 min read

Card descriptions: Testing the effect of contextual information in card sorts

The key purpose of running a card sort is to learn something new about how people conceptualize and organize the information that’s found on your website. The insights you gain from running a card sort can then help you develop a site structure with content labels or headings that best represent the way your users think about this information. Card sorts are in essence a simple technique, however it’s the details of the sort that can determine the quality of your results.

Adding context to cards in OptimalSort – descriptions, links and images

In most cases, each item in a card sort has only a short label, but there are instances where you may wish to add additional context to the items in your sort. Currently, the cards tab in OptimalSort allows you to include a tooltip description, a link within the tooltip description or to format the card as an image (with or without a label).

adding descriptions and images - 640px

We generally don’t recommend using tooltip descriptions and links, unless you have a specific reason to do so. It’s likely that they’ll provide your participants with more information than they would normally have when navigating your website, which may in turn influence your results by leading participants to a particular solution.

Legitimate reasons that you may want to use descriptions and links include situations where it’s not possible or practical to translate complex or technical labels (for example, medical, financial, legal or scientific terms) into plain language, or if you’re using a card sort to understand your participants’ preferences or priorities.

If you do decide to include descriptions in your sort, it’s important that you follow the same guidelines that you would otherwise follow for writing card labels. They should be easy for your participants to understand and you should avoid obvious patterns, for example repeating words and phrases, or including details that refer to the current structure of the website.

A quick survey of how card descriptions are used in OptimalSort

I was curious to find out how often people were including descriptions in their card sorts, so I asked our development team to look into this data. It turns out that around 15% of cards created in OptimalSort have at least some text entered in the description field. In order to dig into the data a bit further, both Ania and I reviewed a random sample of recent sorts and noted how descriptions were being used in each case.

We found that out of the descriptions that we reviewed, 40% (6% of the total cards) had text that should not have impacted the sort results. Most often, these cards simply had the card label repeated in the description (to be honest, we’re not entirely sure why so many descriptions are being used this way! But it’s now in our roadmap to stop this from happening — stay tuned!). Approximately 20% (3% of the total cards) used descriptions to add context without obviously leading participants, however another 40% of cards have descriptions that may well lead to biased results. On occasion, this included linking to the current content or using what we assumed to be the current top level heading within the description.

Use of card descriptions

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Testing the effect of card descriptions on sort results

So, how much influence could potentially leading card descriptions have on the results of a card sort? I decided to put it to the test by running a series of card sorts to compare the effect of different descriptions. As I also wanted to test the effect of linking card descriptions to existing content, I had to base the sort on a live website. In addition, I wanted to make sure that the card labels and descriptions were easily comprehensible by a general audience, but not so familiar that participants were highly likely to sort the cards in a similar manner.

I selected the government immigration website New Zealand Now as my test case. This site, which provides information for prospective and new immigrants to New Zealand, fit the above criteria and was likely unfamiliar to potential participants.

Card descriptions

Navigating the New Zealand Now website

When I reviewed the New Zealand Now site, I found that the top level navigation labels were clear and easy to understand for me personally. Of course, this is especially important when much of your target audience is likely to be non-native English speaking! On the whole, the second level headings were also well-labeled, which meant that they should translate to cards that participants were able to group relatively easily.

There were, however, a few headings such as “High quality” and “Life experiences”, both found under “Study in New Zealand”, which become less clear when removed from the context of their current location in the site structure. These headings would be particularly useful to include in the test sorts, as I predicted that participants would be more likely to rely on card descriptions in the cases where the card label was ambiguous.

Card Descriptions2

I selected 30 headings to use as card labels from under the sections “Choose New Zealand”, “Move to New Zealand”, “Live in New Zealand”, “Work in New Zealand” and “Study in New Zealand” and tweaked the language slightly, so that the labels were more generic.

card labels

I then created four separate sorts in OptimalSort:Round 1: No description: Each card showed a heading only — this functioned as the control sort

Card descriptions illustrations - card label only

Round 2: Site section in description: Each card showed a heading with the site section in the description

Card descriptions illustrations - site section

Round 3: Short description: Each card showed a heading with a short description — these were taken from the New Zealand Now topic landing pages

Card descriptions illustrations - short description

Round 4:Link in description: Each card showed a heading with a link to the current content page on the New Zealand Now website

Card descriptions illustrations - link

For each sort, I recruited 30 participants. Each participant could only take part in one of the sorts.

What the results showed

An interesting initial finding was that when we queried the participants following the sort, only around 40% said they noticed the tooltip descriptions and even fewer participants stated that they had used them as an aid to help complete the sort.

Participant recognition of descriptions

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Of course, what people say they do does not always reflect what they do in practice! To measure the effect that different descriptions had on the results of this sort, I compared how frequently cards were sorted with other cards from their respective site sections across the different rounds.Let’s take a look at the “Study in New Zealand” section that was mentioned above. Out of the five cards in this section,”Where & what to study”, “Everyday student life” and “After you graduate” were sorted pretty consistently, regardless of whether a description was provided or not. The following charts show the average frequency with which each card was sorted with other cards from this section. For example in the control round, “Where & what to study” was sorted with “After you graduate” 76% of the time and with “Everyday day student life” 70% of the time, but was sorted with “Life experiences” or “High quality” each only 10% of the time. This meant that the average sort frequency for this card was 42%.

Untitled chartCreate bar charts

On the other hand, the cards “High quality” and “Life experiences” were sorted much less frequently with other cards in this section, with the exception of the second sort, which included the site section in the description.These results suggest that including the existing site section in the card description did influence how participants sorted these cards — confirming our prediction! Interestingly, this round had the fewest number of participants who stated that they used the descriptions to help them complete the sort (only 10%, compared to 40% in round 3 and 20% in round 4).Also of note is that adding a link to the existing content did not seem to increase the likelihood that cards were sorted more frequently with other cards from the same section. Reasons for this could include that participants did not want to navigate to another website (due to time-consciousness in completing the task, or concern that they’d lose their place in the sort) or simply that it can be difficult to open a link from the tooltip pop-up.

What we can take away from these results

This quick investigation into the impact of descriptions illustrates some of the intricacies around using additional context in your card sorts, and why this should always be done with careful consideration. It’s interesting that we correctly predicted some of these results, but that in this case, other uses of the description had little effect at all. And the results serve as a good reminder that participants can often be influenced by factors that they don’t even recognise themselves!If you do decide to use card descriptions in your cards sorts, here are some guidelines that we recommend you follow:

  • Avoid repeating words and phrases, participants may sort cards by pattern-matching rather than based on the actual content
  • Avoid alluding to a predetermined structure, such as including references to the current site structure
  • If it’s important that participants use the descriptions to complete the sort, you should mention this in your task instructions. It may also be worth asking them a post-survey question to validate if they used them or not

We’d love to hear your thoughts on how we tested the effects of card descriptions and the results that we got. Would you have done anything differently?Have you ever completed a card sort only to realize later that you’d inadvertently biased your results? Or have you used descriptions in your card sorts to meet a genuine need? Do you think there’s a case to make descriptions more obvious than just a tooltip, so that when they are used legitimately, most participants don’t miss this information?

Let us know by leaving a comment!

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