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5 Essential Usability Metrics in UX Research

 By Userlytics
 Feb 06, 2024
Home  »  Blog   »   5 Essential Usability Metrics in UX Research

Ever launched a new feature, expecting fireworks but got crickets instead? You’re not alone. That gap between what we think users want and what they actually do is where usability metrics come to the rescue.

Like a trusty GPS for navigating the user experience wilderness, these usability metrics guide us from the land of guesswork to the haven of user satisfaction. In this article, we unpack the five most important usability metrics that’ll show you whether your product is a hit or a miss when doing a usability test.

What are Usability Metrics?

Usability metrics are the superheroes in the world of UX design and usability testing, providing a treasure trove of quantitative data into user-product interactions -which add up to any qualitative data you can muster.

These metrics form the backbone of user experience research, turning the spotlight on everything from task completion rates to user satisfaction. With usability testing metrics in your toolkit, you’re equipped to unearth vital insights that steer your product development in the right direction.

Essentially, these metrics are your secret weapon to crafting products that truly vibe with your users, ensuring every level of interaction is nothing short of remarkable.

The Different Types of Usability Metrics

To understand how key usability metrics can be measured and evaluated, we need to understand what their purpose is. We’ll introduce the 5 most important usability metrics: Usability, User Satisfaction, Engagement, Conversion Rate, and Retention Rate.


Usability is the bedrock of UX research, focusing on how effectively, efficiently, and satisfactorily a user can interact with a product. The overall usability score is determined by focusing on three key metrics:

Task Success Rate

Example: Consider an e-commerce platform where you want to evaluate the effectiveness of the checkout process.

How to Calculate the Task Success Rate: Number of Successful Checkouts / Total Checkout Attempts x 100. This usability metric is a direct indicator of how intuitively users can navigate through the buying process.

Error Rate

For example, users frequently misinterpret a ‘save for later’ button for ‘add to cart’. Calculate the Error Rate with this formula: Total Number of Misinterpretations / Total Number of Attempts x 100. This usability metric pinpoints where the product’s design might be causing confusion.

Time on Task

For example, the average number of seconds or minutes users spend finding a product using the search function. The formula to calculate Time on Task is: Total Search Time / Number of Searches.

User Satisfaction Score

User satisfaction reflects how users feel about your product. This metric encompasses various aspects of the emotional and psychological responses elicited by the user experience. Tools such as the System Usability Scale (SUS), Net Promoter Score (NPS), and Customer Satisfaction Score (CSAT) are instrumental in capturing user satisfaction.

These metrics act like feedback megaphones, amplifying the voice of the user to give you a crystal-clear snapshot of their satisfaction.  Let’s unpack each one of these metrics.

The System Usability Scale (SUS)

How to Calculate the System Usability Scale (SUS): The SUS score is derived from a standardized 10-question survey, providing a global view of subjective metrics. Participants are asked to express their level of agreement or disagreement with various statements about systems, websites, apps, or prototypes, using prompts like “Please indicate how much you agree or disagree.”

Net Promoter Score (NPS)

Example: Post-interaction, users indicate their likelihood of recommending your service.

How to Calculate the Net Promoter Score (NPS): % Promoters (users who score 9-10, showing they’re highly likely to recommend the service) – % Detractors (users who give a score of 0-6, indicating they’re unlikely to recommend). This usability metric offers insights into user loyalty and satisfaction.

 Customer Satisfaction Score (CSAT)

Example: Users rate their satisfaction with a feature update.

How to Calculate the Customer Satisfaction Score (CSAT): (Sum of Satisfaction Scores / Number of Responses) x 100. This usability metric gauges immediate user reactions to specific product elements.


Engagement is one of the most important usability metrics. It offers insights into how well users interact with your product. Its key indicators include Session Length, Frequency of Use, and Page Views/Interaction Rates. Let’s go over each one of these.

Session Length

Example: The time users spend per session on a new app feature.

How to Calculate the Session Length: Total Time on Feature / Number of Sessions. This usability metric helps understand how engaging the new feature is.

Frequency of Use

Example: How often users return to the app within a given week.

How to Calculate the Frequency of Use: Total App Opens / Number of Users. A key usability metric for measuring app stickiness.

Page Views/Interaction Rates

Example: The number of pages a user views in one session.

How to Calculate Page Views/Interaction Rates: Total Page Views / Number of Sessions. This usability metric helps identify which content is most engaging or if there are navigation issues.

Conversion Rate

Conversion rate is pivotal in contexts where a specific user action is desired, such as making a purchase or signing up for a service. This usability metric measures the percentage of users who take a desired action, providing insights into the design’s effectiveness in facilitating user goals.

Optimizing the conversion rate is often a primary objective for product marketers and UX designers alike, as it directly correlates with the product’s success. Let’s go over an example and how to calculate this usability metric.

Example: The rate at which visitors to your landing page sign up for a newsletter.

How to Calculate the Conversion Rate: (Number of Sign-Ups / Number of Visitors) x 100. This is an essential usability metric for evaluating the effectiveness of call-to-action elements.

Read: How Userlytics and Blakcbaud collaborated to increase the Conversion Rate of their demo booking form.

Retention Rate

Retention rate is a crucial usability metric for understanding how many users continue to use a product over time. It is especially important for services that rely on prolonged user engagement, such as subscription-based platforms. A high retention rate suggests that users find continued value in the product, highlighting its long-term viability.

Example: The percentage of users who continue to use the app after their first month.

How to Calculate the Retention Rate: (Number of Users at End of Month / Number of New Users) x 100. This usability metric is crucial for assessing long-term user satisfaction and product loyalty.

Download our Whitepaper: How A Positive User Experience Can Ensure Customer Retention And Upsell Within Subscription Businesses

Why is it Important to Measure Usability Metrics?

Incorporating usability metrics into your development cycle is beyond standard practice—it’s a necessity to create succesfull products. These metrics (Usability, User Satisfaction, Engagement, Conversion Rate, and Retention Rate) offer unique, objective data that can confirm or challenge your assumptions, allowing you to confidently iterate.

Usability metrics together form the foundation of a strategy that prioritizes user needs, leading to higher satisfaction, increased engagement, and ultimately, business success.

User-Centric Design

These metrics help ensure that products and services are designed with the end user in mind. By measuring how easily users can interact with a system or product, designers can identify areas for improvement and make adjustments to enhance the overall user experience.

Identifying Pain Points

Usability metrics provide insights into areas where users may encounter difficulties or frustrations. By pinpointing these pain points, designers and developers can focus their efforts on addressing specific issues to improve overall usability.

Optimizing User Experience

By measuring usability metrics, organizations can optimize the user experience to increase user satisfaction and engagement. A seamless and intuitive user experience can lead to higher user retention rates and ultimately drive business success.

Validating Design Decisions

With usability metrics, you get the best of objective data to validate design decisions. Instead of relying solely on subjective opinions or assumptions, designers can use metrics such as task completion rates, error rates, and time on task to assess the effectiveness of different design choices.

Comparing Designs

Usability metrics allow for the comparison of different design variations to determine which one performs better in terms of usability. This comparative analysis helps designers make informed decisions about which design elements to prioritize and which ones to refine or discard.

Quantifying Improvement

You can rely on usability metrics to enable organization to quantify the impact of usability improvements over time. By tracking changes in key metrics before and after implementing design enhancements, organizations can measure the effectiveness of their efforts and justify investments in usability initiatives.

Get a 360° view of your User Experience with the ULX ® Benchmarking Score

But here’s the twist: usability metrics are just the tip of the iceberg. Imagine your app or website is very user-friendly (high on usability metrics) but fails to draw users in (low appeal) – not quite the win you hoped for, right? Or it’s engaging but doesn’t pop up in people’s minds when they need your product or service. 

The UX Consulting team of Userlytics came up with the ULX® Benchmarking Score, which gives you a 360°, all-angles view of user experience. It goes beyond mere usability metrics by evaluating 18 attributes spread across 8 key areas, something most tools miss.

This holistic user experience metric has been fine-tuned through rigorous statistical analysis, thanks to our massive panel of over two million participants and extensive UX testing. It gives you the power to benchmark your products over time, against competitors, and across different versions.

It hands you three vital pieces of information: a comprehensive overall score, detailed scores for each of the 8 categories like Usability, Trust, and Appeal, and individual scores for the 18 key attributes, offering a crystal-clear snapshot of your product’s performance. This exclusive diagnostic solution, only available through Userlytics, is your ticket to mastering UX.

How to Calculate Essential Usability Metrics

Calculating essential usability metrics involves measuring various aspects of user interaction with a product or system. Here are some common usability metrics and how to calculate them.

Task Success Rate

Calculate the percentage of tasks successfully completed by users out of the total number of tasks attempted.
The formula is: Number of tasks successfully completed / Total number of tasks attempted x 100. Additionally, you can gauge task difficulty in the shape of a post-test questionnaire.

Time on Task

This metric allows you to measure the average time it takes for users to complete specific tasks. To calculate it, just apply the following formula: Total time spent on task / Number of users attempting the task.

Error Rate

Calculate the percentage of errors made by users while attempting tasks. To measure error rate, just divide Number of errors made / Total number of actions and multiply by 100.

Satisfaction Metrics

Use surveys or questionnaires to collect user feedback on satisfaction. Typically, satisfaction scores are measured on a scale (e.g., 1 to 5 or 1 to 10), and the average score is calculated. They include Test Level Satisfaction and Task Level Satisfaction.

Usability Problem Severity

With this metric, you can assess the severity of usability issues encountered by users during testing. Here, it’s important that you assign severity ratings (e.g., low, medium, high) to each identified problem based on its impact on user experience.

System Usability Scale (SUS)

Calculate an overall usability score based on responses to a standardized questionnaire, the System Usability Scale. Detailed instructions and scoring guidelines for SUS can be found in the original article by John Brooke.

Task Completion Time

Measure the time taken by user “a” to complete task “1”. Track the start and end times for each completed task and calculate the difference. Also, task completion rate can be measured: it is usually presented as a binary value of “1” if users completed the task and “0” if they didn’t.

Navigation Path Analysis

Analyze user navigation paths within a digital product or website to identify patterns, dead ends, or confusion points. Use tools like Google Analytics or specialized user tracking software to gather this data.

Click Through Rate (CTR)

Measure the percentage of users who click on a specific element (e.g., button, link) out of the total number of users who view the element. The formula is: Number of clicks on element / Number of views of element x 100.

Abandonment Rate

Calculate the percentage of users who leave a process or task before completion. The formula is: Number of users who abandon task / Total number of users starting task x 100.

These are just some examples of essential usability metrics, and the specific metrics you choose to measure will depend on your project goals, the nature of your product or system, and the preferences of your stakeholders.

It’s important to define clear objectives and select metrics that align with those objectives to effectively evaluate usability and inform design decisions.


The strategic application of usability metrics is indispensable in creating outstanding digital products. They enable you to translate user behaviors and preferences into actionable insights, driving the design of intuitive and enjoyable user experiences. By committing to a rigorous analysis of usability metrics, you guarantee that every design decision is informed, and you can ensure your products not only meet but exceed user expectations.

The usability metrics discussed in this article are seamlessly integrated into the Userlytics platform, allowing you to easily set them up and track them on your own. Why not schedule a free demo or have a conversation with our team to learn more?

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