If you are trying to measure success for UX/UI, web design KPIs are great options. After all, you want to design a great experience for users. You cannot really be sure whether you have done that or not, unless you measure KPIs and see what they tell you. If you are not getting good user engagement, or you find that your users are not coming back, that tells you that you may need to make some changes. Here are the main UX/UI KPI areas you want to look at, to provide the most value and information.

Average Time on Task

Knowing how long it takes for a user to complete a task matters. Generally, the faster the task completion the better the UX. You can also look at first attempts and repeat attempts, if you want to break this metric down into something even more detailed. For repetitive, frequent tasks that users must complete, this is one of the best web design KPIs to give you important information about the quality of what you are offering and how well it works for users.

The best way to measure average time on task is to measure the duration of the entire task, and then look at the average time on a particular screen or activity. That can help you see where slowdowns are occurring or which steps are taking too long.

Task Completion Rate

Understanding how many users complete all the steps to a task and actually complete it is another important UX/UI KPI. This is also often called the task success rate, and it works well for any defined task with a clear staring and ending point. This does not diagnose problems, but it does tell you where the UX might be breaking down due to confusion or a level of effort that the user finds to be too much.

The task completion rate is measured by looking at all tasks and all users for a given time period. If there are three tasks, for example, and the rates are 50%, 70%, and 85%, then the overall task completion rate is (50+70+85)/3, or 68.3%.

Error Occurrence Rate

If you want to know where any of your users might be struggling with your product, the error occurrence rate can give you that information. Users making infrequent mistakes is understandable, but if a high percentage of users are making the same mistake in the same place, that could signal that you need to make changes to the UI. You may also want to consider simplifying the task, or providing more training. Not being able to move through the steps can mean a lower ROI for you, if users give up.

To calculate the error occurrence rate, simply divide the total number of errors by the total number of opportunities for errors, for all users. If multiple errors are possible for each task, you can divide the number of errors by the total number of attempts.

Retention Rate

To see the percentage of users who keep using your product for the long term, you need web design KPIs on the retention rate. Looking at daily active users versus new users helps you see how many of the current users are those who have been with you for a while. Product lifecycle matters here, since a product with a short lifecycle cannot be expected to have long-term retention rates. Retaining users is another good way to measure ROI, since you want to keep the users you get, along with bringing on more.

Calculating the retention rate is important, since you want to keep users coming back. You can find this information by using the formula [(E-N)/S] x 100 = CRR. In other words, for a given time frame, you need the number of customers at the start (S), the number at the end (E), and the number of new customers added in that time period (N). Plug in the numbers and multiply by 100, to get a retention rate percentage.

Net Promoter Score

The net promoter score (NPS) asks users to indicate how likely they are to recommend your product to others. A 1-10 scale is generally used for this, ranging from not at all likely to extremely likely. Finding out whether a user would recommend your product gives you a good idea of whether they like it, and whether they will continue to use it in the future. If users go out of their way to promote your product, that can help your company grow without any extra effort on your part, thus improving your ROI.

By looking at the answers on the 1-10 scale, you can calculate your NPS. Promoters are those who marked 9-10, passives marked 7-8, and detractors marked 6 or lower. Subtracting the detractor percentage from the promoter percentage gives you your NPS.

Customer Satisfaction

Much like your net promoter score, customer satisfaction is a big part of UX/UI KPIs. If customers are not satisfied, they are not going to keep using your product or recommend it to others. They may even decide that they will warn people away from using your product, and try to discourage current users from continuing to use it, as well. Unsatisfied customers can really harm your business, especially if there are a lot of them, so correcting problems with customer satisfaction should be a serious priority.

By asking customers who satisfied they are, with 1 being very dissatisfied and 5 being very satisfied, you can calculate your customer satisfaction score by using the number of people rating you 4 or 5, dividing that by the total responses, and then multiplying that number by 100.

System Usability Scale

You can use the system usability scale (SUS) to find out more detailed information than you can get from the customer satisfaction or NPS questions. The original SUS uses a set of survey questions created back in 1986, to help product designers determine how much users liked the product and would continue to use it. How easy it was to use was also part of the survey. While you can modify the survey questions, they are all still very relevant today. The questions can be asked through email, phone, or face-to-face.

The SUS is calculated by converting the scale into numbers, with 1 being very dissatisfied and 5 being very satisfied. For questions with odd numbers, subtract 1 from the score (X). Subtract their value from five for every even-numbered question (Y). Then sum the numbers (X+Y) and multiply by 2.5. That gives you a score based on perceived system usability. A score above 68 is your goal.

Single Sign-On Capabilities

It is no secret that single sign-on capabilities make everything easier for users. It allows users to access multiple features or tools, all from one account. That gives users a cross-platform experience that is not nearly as difficult to work through, and can reduce frustration. Managing passwords is easier with single sign-on, and there are fewer reset requests for passwords when your website has this option for users. Making things less complicated can result in users coming back more readily.

Single sign-on options need to be tested for their ability to let users log in properly, and also to log out correctly. Encryption matters throughout the entire process. Fortunately, Testim, OneLogin, and other companies have software options to test your site’s security and abilities.

Mobile-Friendly Design

You really should be thinking about mobile-first or at least mobile-friendly design, given the number of people who use their devices to search for information and complete tasks. Users expect their digital products to have seamless availability across all devices and platforms. If you are not offering that to users, you are losing out on ROI that you could increase with proper design. Users want to be able to access your platform anytime they like, and that means a better UX for them.

Testing a mobile-friendly design is relatively easy. Check out your site and all its capabilities on as many devices and operating systems as possible, to determine if there are bugs or other problems. For example, it might work great on an iPhone, but not as well on an Android phone. By finding that out quickly, you can give more users a good experience.

Scalable Systems

Scaling up is something you want to see your users do. That means they like your product enough to keep using it, and also to build on what they already do with it. Naturally, that can mean a better ROI for you over time, because you retain users and also get them using more of what you are offering. Synchronization across platforms and options for collaboration will help take your web design to the next level. Measuring the scalability of your system, and how many users are taking advantage of that, is important.

To test for scalability, look into your website’s response time. throughput, screen transitions, network and memory usage, requests per second, and how long it takes for task execution. If it’s struggling in any of those areas, it may not be as scalable as you need.

The Bottom Line on KPIs for UX/UI

It is easy to see why web design KPIs are so significant in increasing the success of your company and its products. With a good understanding of UX/UI KPI value, you can make smart choices that will help your company grow. Learning what users like and do not like about the products you already provide helps you adjust those products successfully. Additionally, you can create more products based on user feedback, and those products will have a head start due to pre-collected information.