February 27, 2023

The Role of Usability Metrics in User-Centered Design

The term ‘usability’ captures sentiments of how usable, useful, enjoyable, and intuitive a website or app is perceived by users. By its very nature, usability is somewhat subjective. But what we’re really looking for when we talk about usability is how well a website can be used to achieve a specific task or goal. Using this definition we can analyze usability metrics (standard units of measurement) to understand how well user experience design is performing.

Usability metrics provide helpful insights before and after any digital product is launched. They help us form a deeper understanding of how we can design with the user front of mind. This user-centered design approach is considered the best-practice in building effective information architecture and user experiences that help websites, apps, and software meet and exceed users' needs.

In this article, we’ll highlight key usability metrics, how to measure and understand them, and how you can apply them to improve user experience.

Understanding Usability Metrics

Usability metrics aim to understand three core elements of usability, namely: effectiveness, efficiency, and satisfaction. A variety of research techniques offer designers an avenue for quantifying usability. Quantifying usability is key because we want to measure and understand it objectively, rather than making assumptions.

Types of Usability Metrics

There are a few key metrics that we can measure directly if we’re looking to quantify effectiveness, efficiency, and satisfaction. Here are four common examples:

  • Success rate: Also known as ‘completion rate’, success rate is the percentage of users who were able to successfully complete the tasks.
  • Time-based efficiency: Also known as ‘time on task’, time-based efficiency measures how much time a user needs to complete a certain task.
  • Number of errors: Sounds like what it is! It measures the average number of times where an error occurred per user when performing a given task.
  • Post-task satisfaction: Measures a user's general impression or satisfaction after completing (or not completing) a given task.

How to Collect Usability Metrics


Usability metrics are outputs from research techniques deployed when conducting usability testing. Usability testing in web design, for example, involves assessing how a user interacts with the website by observing (and listening to) users completing defined tasks, such as purchasing a product or signing up for newsletters.

Conducting usability testing and collecting usability metrics usually involves:

  • Defining a set of tasks that you want to test
  • Recruitment of test participants
  • Observing participants (remotely or in-person)
  • Recording detailed observations
  • Follow-up satisfaction survey or questionnaire

Tools such Reframer are helpful in conducting usability tests remotely, and they enable live collaboration of multiple team members. It is extremely handy when trying to record and organize those insightful observations! Using paper prototypes is an inexpensive way to test usability early in the design process.

The Importance of Usability Metrics in User-Centered Design

User-centered design challenges designers to put user needs first. This means in order to deploy user-centered design, you need to understand your user. This is where usability testing and metrics add value to website and app performance; they provide direct, objective insight into user behavior, needs, and frustrations. If your user isn’t getting what they want or expect, they’ll simply leave and look elsewhere.

Usability metrics identify which parts of your design aren’t hitting the mark. Recognizing where users might be having trouble completing certain actions, or where users are regularly making errors, are vital insights when implementing user-centered design. In short, user-centered design relies on data-driven user insight.

But why hark on about usability metrics and user-centered design? Because at the heart of most successful businesses is a well-solved user problem. Take Spotify, for example, which solved the problem of dodgy, pirated digital files being so unreliable. People liked access to free digital music, but they had to battle viruses and fake files to get it. With Spotify, for a small monthly fee, or the cost of listening to a few ads, users have the best of both worlds. The same principle applies to user experience - identify recurring problems, then solve them.

Best Practices for Using Usability Metrics

Usability metrics should be analyzed by design teams of every size. However, there are some things to bear in mind when using usability metrics to inform design decisions:

  • Defining success: Usability metrics are only valuable if they are being measured against clearly defined benchmarks. Many tasks and processes are unique to each business, so use appropriate comparisons and targets; usually in the form of an ‘optimized’ user (a user with high efficiency).
  • Real user metrics: Be sure to test with participants that represent your final user base. For example, there’s little point in testing your team, who will likely be intimately aware of your business structure, terminology, and internal workflows.
  • Test early: Usability testing and subsequent usability metrics provide the most impact early on in the design process. This usually means testing an early prototype or even a paper prototype. Early testing helps to avoid any significant, unforeseen challenges that could be difficult to rewind in your information architecture.
  • Regular testing: Usability metrics can change over time as user behavior and familiarity with digital products evolve. You should also test and analyze the usability of new feature releases on your website or app.

Remember, data analysis is only as good as the data itself. Give yourself the best chance of designing exceptional user experiences by collecting, researching, and analyzing meaningful and accurate usability metrics.

Conclusion

Usability metrics are a guiding light when it comes to user experience. As the old saying goes, “you can’t manage what you can’t measure”. By including usability metrics in your design process, you invite direct user feedback into your product. This is ideal because we want to leave any assumptions or guesswork about user experience at the door.

User-centered design inherently relies on constant user research. Usability metrics such as success rate, time-based efficiency, number of errors, and post-task satisfaction will highlight potential shortcomings in your design. Subsequently, they identify where improvements can be made, AND they lay down a benchmark to check whether any resulting updates addressed the issues.

Ready to start collecting and analyzing usability metrics? Check out our guide to planning and running effective usability tests to get a head start!

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A comprehensive look at usability testing

Usability testing has an important role in UX and if you’re new to it, this article gives you a solid introduction to it with practical tips, a checklist for success and a look at our remote testing tool, Treejack.

Concepts Of usability testing 👩🏾💻

Usability testing is the process of evaluating a product or service with users prior to implementation. The goal of usability testing is to identify any usability issues before the product or service is released into the world for use. Usability testing is a research activity that results in both quantitative and qualitative insights and can be used to gauge user satisfaction.A typical usability testing session is moderated and involves a participant, a facilitator and an observer. The facilitator leads the session and the observer takes notes while the participant completes the task based scenario.

While this is common, usability testing is scalable and the possible approaches are endless giving you the flexibility to work with the resources you have available—sometimes one person performs the role of facilitator and observer!Location also varies for usability testing. For example, you might conduct your testing in a lab environment or you might talk to users in a specific environment. It also worth noting that not all usability testing sessions are moderated—more about this later.Usability testing usually occurs multiple times during the design process and can be conducted anytime you have a design you would like to test.

User research activities like a focus group for example, are conducted early in the design process to explore and gain understanding before ideas are generated. Usability testing is about testing those ideas as early and as often as possible. From a fully functioning digital prototype to a simple hand drawn wireframe on paper, nothing is too unrefined or too rough to be tested.

Developing a usability test plan 🛠️

Before you start a round of usability testing, you need to develop a usability test plan. The usability test plan will keep you organised and is an opportunity to define roles and set clear expectations upfront. The first step in developing this is to hold a meeting with your team and stakeholders to discuss what you are going to do and how you plan to achieve it. Following this meeting, a document outlining the usability test plan as it was discussed is created and shared with the group for review. Any changes suggested by the group are then added to the final document for approval from the relevant stakeholders.

What to include in your usability test plan:

  • The goal, scope and intent of the usability testing
  • Constraints impacting upon testing
  • Details on what will be tested eg wireframes
  • Schedule and testing location
  • Associated costs eg participant recruitment
  • Facilitator and observer details for each session
  • Session details
  • Participant recruitment approach
  • Equipment
  • Details of any documentation to be produced eg a report

Usability testing questions 🤔

Once you have developed your test plan, you need to create a list of questions and task based scenarios for the testing session. These form the structure for your testing and provide a framework of consistency across all testing sessions in the study.The questions serve as a warm up to ease the participant into the session and can also provide insights on the user that you may not have had before. These questions can be a combination of open and closed questions and are especially useful if you are also developing personas for example. Some examples of what you might ask include:

  • Tell me about a recent experience you had with this product/service
  • Do you currently use this product/service?
  • Do you own a tablet device?

The purpose of the task based scenarios is to simulate a real life experience as closely as possible. They provide a contextual setting for the participant to frame their approach and they need to be realistic—your participant needs an actionable starting point to work from. A good starting point for task based scenario development would be to look at a use case.It is also important that you avoid using language that provides clues to the solution or leads your participant as this can produce inaccurate results. An example of a task based scenario would be:You’re planning a Christmas vacation to New Zealand for your family of two adults and 4 children. Find the lowest priced airfares for your trip.

Usability testing software: Tree testing 🌲🌳🌿

Treejack is a remote information architecture (IA) validation tool that shows you exactly where users are getting lost in your content. Knowing this will enable you to design a structure for your website that makes sense to users before moving on to the user interface (UI) design.Treejack works like a card sort in reverse. Imagine you have just completed a card sort with your users to determine your IA and you are now working backwards to test that thinking against real world task based scenarios. Treejack does this using a text-based version of your IA that is free from distracting visual aids such as navigation and colour allowing you to determine if your structure is usable from the ground up. A Treejack study is structured around task based scenarios and comes with the option to include pre and post study questionnaires.

treejack task image
Usability testing with Treejack

As a remote testing tool, Treejack is unmoderated and provides the opportunity to reach a much larger audience because all you have to do is share a link to the study with your participants to gain insights. You also have the option of handing the task of targeted participant recruitment over to Optimal Workshop.Once launched and shared with participants, Treejack takes care of itself by recording the results as they come in giving you the freedom to multitask while you wait for the testing to finish.

The results produced by Treejack are not only detailed and comprehensive but are also quite beautiful. The story of your participants’ journey through your testing activity is told through pietrees. A pietree is a detailed pathway map that shows where your participants went at each fork in the road and their destinations. They allow you to pinpoint exactly where the issues lie and are a powerful way to communicate the results to your team and stakeholders.

bananacom pie tree
Treejack presents your results using pietrees

Treejack also provides insights into where your participants landed their first click and records detailed information on pathways followed by each individual participant.

bananacom paths
Treejack records full details of the paths followed by every participant

Usability testing checklist 📋

The following checklist will help ensure your usability testing process runs smoothly:

  • Meet with team and stakeholders
  • Determine goals, scope and intent of usability testing
  • Decide how many sessions will be conducted
  • Create usability testing schedule
  • Select facilitators and observers for each session if applicable
  • Develop and complete a usability test plan
  • Determine test questions and scenarios
  • Recruit participants for testing
  • Gather equipment required for testing if applicable
  • Book testing location if applicable
  • Keep a list of useful contact details close by in case you need to contact anyone during testing
  • Complete a dry run of a testing session with a team member to ensure everything works before actual testing begins
  • Organise debrief meetings with observers after each testing session
  • Set aside time to analyse the findings
  • Document and present findings to team and relevant stakeholders

Related reading 📚🎧☕

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Why information architecture is the foundation of UX

Ever wondered what the relationship is between information architecture (IA) and UX? Simply put, IA is the foundation of UX. We outline why.

What is Information Architecture? 🛠️

According to Abby Covert, a leader in the field of information architecture, IA is ‘the way we arrange the parts to make sense of the whole.’ This can relate to a website, a retail store or an app. And you could even consider the way a library is sorted to be information architecture. For the purposes of this article, we will focus on digital products (apps or websites).

Well-organized information architecture is fundamentally important to the success of your product. As a designer, knowing the content you are delivering and how, is fundamental to creating a UX that performs. Working with the needs of the organization and meeting the requirements of the users in a meaningful and delightful way. Organizing and structuring the information so that navigating, searching, and understanding your product is seamless is ultimately what UX design is all about. Arranging the parts to make sense of the whole, you could say.

While design is about creating visual pointers for users to find their way, information architecture can be broken down into 3 main areas to consider when building a great user experience:

  • Navigation: How people make their way through information 
  • Labels: How information is named and represented.
  • Search: How people will look for information (keywords, categories)

When put like this it does seem pretty straightforward. Maybe even simple? But these tasks need to be straightforward for your users. Putting thought, time, and research at the front of your design and build can increase your chances of delivering an intuitive product. In fact, at any point in your product’s life cycle, it’s worth testing and reviewing these 3 areas.  

Key things to consider to build an effective IA for UX 🏗

Developing a well-thought-out and researched information architecture for your product could be considered a foundation step to creating a great UX product. To help you on your way, here are 6 key things to consider when building effective information architecture for a great user experience. 

  1. Define the goals of your organization: Before starting your IA plan, uncover what is the purpose of your product and how this will align with the goals of your stakeholders.
  2. Figure out your user’s goals: Who do you want to use your product? Create scenarios, discuss with probable users and find out what they’ll use your product for and how they’ll use it.  
  3. Study your competitors: Take note of websites, apps and other digital products that are similar to yours and look at their information architecture from a UX point of view. How does the design work with the IA. Is it simple to navigate? Easy to find what to do next?  Look at how key information is designed and displayed.
  4. Draw a site map: Once the IA is planned and developed and the content is ready, it’s time to figure out how users are going to access all of your information. Spend time planning navigation that is not too complex that will help users to browse your product easily. 
  5. Cross browser testing: Your information architecture behavior may vary from one browser so it’s worth doing some cross-browser compatibility testing. It would be very disappointing to work so hard to get the best UX with your product, only to be let down because of browser variances.
  6. Usability testing: End users are the perfect people to let you know how your product is performing. Set up a testing/staging environment and test on external users. Observing your participants while they move their way through your product uninterrupted and listening to their opinions can shed light on the successes (and failures) in a very insightful way. 

Wrap Up 🌯

Information architecture is the foundation of designing a great product that meets (or even exceeds) your users’ needs, wants, and desires. By balancing an organization’s needs with insight into what users actually want, you’re well equipped to design an information architecture  that helps build a product that delivers a positive user experience. Research, test, research, and test again should be the mantra throughout the development, design, and implementation of your product and beyond.

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Why information architecture is important for designers

Sitting inside any beautifully crafted and designed digital product, there must be a fully functional and considered information architecture.

As much as information architecture shouldn’t be developed in a vacuum. Neither should the design and look of digital products. In fact, a large proportion of the function of digital designers is devoted to supporting users locating content they need and driving them towards content that the product owners want them to find.

Incorporating visual markers to make sure that certain content is distinct from the rest or creating layers that demonstrate the diverse content on a product.

If you do not have quality content, it is impossible to design a quality digital product. It all comes back to creating a user experience that makes sense and is designed to make task completion simple. And this relates back to designing the product with the content planned for it in mind.

8 Principles of information architecture, according to Dan Brown 🏗️

As a designer, the more you know about information architecture, the better the products you design will meet your user requirements and deliver what they need. If you work with an information architect, even better. If you’re still learning about information architecture the 8 Principles according to Dan Brown is a great place to begin.

If you haven’t come across Dan Brown yet, you have more than likely come across his 8 principles. Dan Brown is one of the UX world's most prolific experts with a career that spans most areas of UX designs. He’s written 3 books on the subject and experience across a multitude of high profile projects. Aiding large organizations to make the most of their user experience.

  1. The principle of objects: Content should be treated as a living, breathing thing. It has lifecycles, behaviors, and attributes.
  2. The principle of choices: Less is more. Keep the number of choices to a minimum.
  3. The principle of disclosure: Show a preview of information that will help users understand what kind of information is hidden if they dig deeper.
  4. The principle of examples: Show examples of content when describing the content of the categories.
  5. The principle of front doors: Assume that at least 50% of users will use a different entry point than the home page.
  6. The principle of multiple classifications: Offer users several different classification schemes to browse the site’s content.
  7. The principle of focused navigation: Keep navigation simple and never mix different things.
  8. The principle of growth: Assume that the content on the website will grow. Make sure the website is scalable.

It’s highly likely that you’ve already used some, or all, of these IA principles in your designs. Don’t be shy about mastering them, or at the very least be familiar. They can only help you become a better user experience designer.

Wrap up 🌯

Mastering the 8 principles, according to IA expert Dan Brown will see you mastering the complex tasks of information architecture. Understanding IA is key to creating digital designs with a content structure that is functional, logical and just what your users need to navigate your product. Design without good IA doesn’t work as well, just as a content structure without a well designed interface will not engage users.

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