Whenever you build a product or a feature, its success depends on its usability rather than the design. Though good design matters, what matters more is whether people can actually use your product well. But how do you measure that usability or user experience? Is there a way to quantify data?
This is where usability testing metrics come in. Instead of guessing whether something works well, these metrics provide you with quantifiable data to measure how people interact with your product.
One approach to testing usability is considering the three parameters:
- Effectiveness: How well users can complete a given task
- Efficiency: How quickly they can complete it
- Satisfaction: How users feel about using the product
By assessing these three areas, we can quantify how usable a product is for its users. Whether you're new to product design or have extensive years of experience, this usability testing metrics guide will help you understand why usability metrics are important and what they are.
Quantify usability by tracking key UX metrics with Hubble
Explore how you can measure your product's usability
Why Do You Need to Measure Usability?
Imagine spending months developing a feature, only to find that users are not engaging with it as you had expected. Without concrete data, you're left guessing what went wrong. This is where usability measurement becomes your secret weapon. Here are some solid reasons why you need to measure your product's usability:
Catch Problems Early: By tracking usability metrics, you can spot friction points before they impact your user base. Instead of waiting for user feedback and bug reports, you'll identify and fix issues proactively.
Make Data-Backed Improvements: Stop relying on hunches. When you measure usability, every design decision becomes informed by real user behavior. This means you can prioritize changes that will have the biggest impact on user experience, saving both time and resources.
Prove Your Product's Worth: Stakeholders need more than gut feelings. They need evidence. Usability metrics provide concrete data that justify design decisions and demonstrate ROI. When you can show that a design change improved task completion rates by 40%, you're speaking a language that resonates with decision-makers.
Stay Ahead of Competition: Understanding your product's usability metrics gives you a competitive edge. By benchmarking against industry standards and tracking your progress, you can identify opportunities to outperform competitors and set new standards in your market.
The Three Pillars of Usability Metrics
Generally, there are three factors for quantifying usability. Let's talk about them one by one.
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1. Effectiveness
This defines whether or not a user can complete tasks with your product and how effectively will they be able to do it. You can test this metric by further using two different metrics.
Task Completion Rate
Task completion rate is a primary effectiveness metric that measures the percentage of users who successfully complete a specific task. Calculated by dividing the number of users who complete a task by the total number of users attempting the task, it provides a binary value representation of user success.
According to a study published in 2011, the average task completion rate is 78%. So, if your results are anything above this number, it's a good score to go for. However, a rate below this means: There are a lot of usability problems, and you need to work on them.
Your task completion rate should be your first priority, and at Hubble, we'll help you do that. Generate a success rate for your study and determine where the problem lies with our usability testing tool.
Number of Errors
This metric is the opposite of task success rate. It's about calculating the number of errors users usually encounter while completing a task with your product. Tracking this error rate offers diagnostic insights into user interaction challenges. It defines how many times a user has diverted from your given path to complete the task.
By categorizing and quantifying these errors, designers can identify pain points in the user flow. Here are the types of errors that a user makes:
- Navigation errors
- Input mistakes
- Misunderstanding interface elements
- Incorrect task completion attempts
You can calculate your error rate for the study by dividing the total number of errors by the total number of attempts. You can also save yourself the hassle and let Hubble's usability testing tool perform all the calculations for you.
2. Efficiency
The efficiency metrics basically calculate the amount of effort it takes for a user to complete a task. It also measures the time it takes for a user to complete a task. It takes two metrics to measure the efficiency of your product:
Time-Based Metrics
Time on task and time on screen are critical efficiency measurements. These metrics help quantify the overall relative efficiency of a user interface by tracking how long users take to complete specific tasks.
The time-based efficiency equation considers the following:
- Total time spent on a task
- Number of actions required
- Complexity of the task
For instance, you want your users to finalize a purchase process on your eCommerce platform. Ideally, this will take only a few minutes. But if your user hesitates or takes longer than expected, you might need to look into your UI elements.
3. Satisfaction
By tracking user interaction satisfaction, you will basically evaluate the overall satisfaction rate for your product, which includes perception, preference, and emotional response. Here are some satisfaction metrics that you need to calculate for your product:
System Usability Scale (SUS)
The System Usability Scale (SUS) is your go-to measurement tool. This industry-standard questionnaire consists of 10 simple Likert-scale questions that participants answer after interacting with your product.
Each question is rated from 1 (strongly disagree) to 5 (strongly agree). Here are some example questions:
- "I think I would use this system frequently"
- "I found the system unnecessarily complex"
- "I felt very confident using the system"
The magic number to beat? 68. That's the average SUS score. Anything higher means your product is above average in usability. With Hubble, you can easily track your SUS scores over time and benchmark against industry standards.
Single Ease Question (SEQ)
Sometimes, the simplest metrics are the most powerful. The Single Ease Question (SEQ) asks users one straightforward question right after completing a task:
"Overall, how difficult or easy was this task to complete?" Users rate their experience on a 7-point scale, where 1 means "very difficult" and 7 means "very easy". The average SEQ score hovers around 5.5, giving you a clear benchmark against which to measure.
Hubble automatically presents this question after each task, making it effortless to collect consistent feedback. Low scores? That's your signal to investigate the user flow and identify potential friction points.
Subjective Mental Effort Questionnaire (SMEQ)
Ever wonder how much mental effort your users are putting in? This metric is designed specifically to measure the cognitive load during task completion. This unique questionnaire uses a visual scale from 0-150 millimeters, with nine labeled points ranging from "Not at all hard to do" to "Tremendously hard to do."
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It's particularly valuable when you're redesigning complex workflows, simplifying technical processes, and optimizing multi-step tasks. Hubble makes it easy to implement SMEQ in your usability studies and track changes in cognitive load as you refine your user experience.
Advanced Usability Metric Strategies
You can take your usability testing to the next level with advanced usability testing strategies. This approach will help you get a fuller picture of how people use your product. For instance:
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Benchmarking Against Industry Standards
Think of benchmarking as checking your product's grades against the class average. Here's how to do it:
- Keep track of common metrics in your industry (like average time to complete tasks or success rates)
- Look at similar products and features to set realistic goals
- Set up regular checks to see how you measure up
- Use this info to spot areas where you're falling behind or leading the pack
Tracking Metrics Over Time (Longitudinal Studies)
Tracking metrics over time helps you see how your product grows and changes. Set up regular testing schedules (like monthly checks) and watch how your numbers change when you make updates. Make sure you're using the same testing method each time. This way, you can fairly compare results from different months. And don't forget to keep notes of both good and bad changes, as they'll help you spot patterns over time that show what's working and what isn't.
Competitive Analysis Through Metrics
Competitive analysis is about seeing how you stack up against other similar products. Test your competitors using the same methods you use for your own product. This helps you find what they do better or worse than you. You can then use this information to improve your own product and find gaps in the market that no one else is filling. It's like learning from others' homework. You see what works and what doesn't without making the mistakes yourself.
A/B Testing with Usability Metrics
A/B testing is like running a simple experiment. You make two different versions of something in your product and test them both. Get enough people to try each version, using the same way to measure success for both. Then, you can clearly see which version works better. Just remember to test only one thing at a time; if you change too many things at once, you won't know what actually made things better.
Which usability metrics should you track?
Not all usability metrics work the same way, and you'll need different ones based on what you want to learn about your product. To learn more about the most popular usability metrics used in the industry, check out this section on top usability metrics. Let's break down which metrics matter most for different goals:
Checking how well users complete tasks: Look at task completion rate and number of errors. This tells you if people can actually use your features the way they're meant to.
Understanding task speed: Focus on how much time users spend on each screen and how long it takes them to finish tasks. If something's taking too long, you might need to make it simpler.
Finding where users get stuck: Track where users make mistakes and how often they click the wrong things. These numbers show you exactly where people struggle.
Learning how users feel: Use both quick feedback (like the Single Ease Question) and detailed surveys (like the System Usability Scale) to understand if people actually enjoy using your product.
To learn more in depth about how to choose relevant UX metrics, we recommend our guide on UX metrics and how to choose them. Remember, you don't need to track everything at once. Pick the metrics that match what you're trying to learn. And if counting all these numbers sounds like too much work, that's where Hubble comes in - we track these metrics for you and turn them into clear reports you can use right away.
Why Choose Hubble as Your Usability Testing Platform
Choosing the right usability testing platform can make or break your user research efforts. Here's why Hubble stands out as the premier choice for teams serious about measuring and improving their user experience:
Comprehensive Metric Tracking
Hubble captures every crucial interaction during your usability test session. From task completion rates to time-on-page metrics, our platform automatically collects and organizes data that matters to your team. Say goodbye to manual tracking and hello to effortless, accurate measurement of your user's journey.
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Visualization Capabilities
Transform complex data into clear, actionable insights with Hubble's visualization tools. Our intuitive dashboards present your usability metrics through heat maps, user flow diagrams, and interactive charts. These visual representations make it easy to spot patterns, identify pain points, and share findings with stakeholders.
Integration with Existing Design Workflows
Hubble seamlessly fits into your current design process without disrupting your team's momentum. Connect directly with your favorite design tools, import prototypes with a single click, and share results across your preferred collaboration platforms. We adapt to your workflow, not the other way around.
Support for Both Quantitative and Qualitative Data
Capture the full picture of user experience by combining hard numbers with human insights. Hubble records both quantitative metrics and qualitative feedback like user comments, facial expressions, and think-aloud sessions. This dual approach ensures you understand not just what users do, but why they do it.
Quantifying Usability with Hubble
Usability testing metrics represent a powerful lens for understanding and improving digital experiences. By embracing a data-driven approach, organizations can create more intuitive, efficient, and satisfying user interfaces.
However, you must not over-rely on the quantitative data and balance your metrics with qualitative insights. We recommend picking the most relevant metric for your research goal.
Hubble takes the complexity out of usability testing by automatically tracking the metrics that matter most to your team. We'll give you real-time, actionable feedback for both existing features and early concepts. Start tracking your usability metrics today and unlock the potential of user-centered design.
Quantify usability by tracking key UX metrics with Hubble
Explore how you can measure your product's usability
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