As Steve Jobs says, "Design isn't just how it looks like and feels like. Design is how it works."
Design is much more than art— it aims to solve user problems and provide value!
In this context, User Experience (UX) Key Performance Indicators (KPIs) allow businesses to measure UX efforts while identifying improvement opportunities.
Let's explore what UX KPIs are and how a business should measure them to ensure products that offer world-class UX!
What are User Experience KPIs?
According to the Interaction Design Foundation (IxDF), UX KPIs are quantifiable metrics that show how UX efforts perform.
These KPIs provide actionable insights for informed design decisions by removing personal biases and ensuring user-centered products.
Measuring and tracking UX KPIs is critical to meeting UX strategic business goals!
Types of User Experience KPIs
Behavioral KPIs
In UX Design, Behavioral KPIs are quantitative metrics used to understand user actions when interacting with a digital product.
Behavioral metrics help understand user behavior and uncover issues and areas for improvement.
1. Task Success Rate
Task Success Rate is the percentage of users who complete a task and the number of attempts they take.
This KPI is excellent for spotting usability issues and addressing them promptly.
According to Measuringu, an average completion rate below 78% could mean there are usability issues.
You can calculate the Task Success Rate with this formula:
Task Success Rate = (Number of correctly completed tasks / Total number of attempts) * 100
For example, if 36 out of 93 users managed to complete their tasks, that means that the task success rate equals 80%: (36/93) * 100 = 38,70%
2. Time on Task
Time On Task, or Task Time, represents the time it takes users to complete a specific task.
Low times reflect easy-to-use and intuitive interfaces, whereas long times show it's hard for users to understand how to use the product.
This is the formula to calculate Time On Task:
Average Time On Task = (Average Time Taken To Complete The Task / Total Number Of Users To Complete The Task)
For example, if one user takes 55 seconds to complete a task, a second user takes 71 seconds and a third user 49 seconds, that is a total of 175 seconds.
This number is the average time taken, to get the Average Time On Task, you should divide it by 3, the amount of users: (55+71+49) = 175/3 = 58.33 seconds.
3. User Error Rate
User Error Rate (UER) tracks the amount of mistakes users make when attempting to complete a task.
A high Error Rate is an indicator of usability issues.
You can calculate the User Error Rate KPI with the following formula:
User Error Rate = (Total Number of Errors / Total Number of Attempts) * 100
For example, if 91 users attempt to complete a task once and the total number of errors they make is 32, the User Error Rate would be (32/91) * 100 = 35.165%
4. Error Occurrence Rate
The Error Occurrence Rate measures the frequency of a specific error among several possible ones.
It’s also used to evaluate scenarios with only one potential error.
This is the formula to calculate this rate:
Error Occurrence Rate = (Total Number of Errors for All Users / Total Number of Possible Errors for all Users) * 100
Let’s say users are entering invalid phone numbers or email addresses.
If all users made 38 errors and the number of opportunities for errors was 152, the Error Occurrence Rate would be: (38/152) * 100 = 25%
5. Navigation vs Search
The Navigation vs Search KPI shows the number of users who needed to use the search function to locate specific information.
A high amount of users relying on the search bars or other search methods may indicate that the product's navigation needs revision.
To calculate and present Navigation vs Search, use the following equation:
Navigation vs Search = (Number of Uses / Number of Total Interactions) * 100
For instance, ask 24 users to complete a task on your e-commerce website prototype, such as locating a return policy.
If 13 users relied on the navigation menu and 11 used the search function, the calculation would be 13/24 * 100 = 54,16% for navigation menu and 11/24 * 100 = 45,83% for the search function.
Attitudinal KPIs
Attitudinal KPIs track user feedback on what they think and feel when interacting with a digital product.
These UX metrics focus on understanding how users perceive your product by analyzing their personal opinions.
1. System Usability Scale (SUS)
System Usability Scale is a standard method for measuring a product's usability through a 5-point Likert scale questionnaire.
The questionnaire includes a list of statements such as:
- "I believe I will be able to use this product without the support of a technical person."
- "I found the features and functions unnecessarily complex."
The users will have 5 possible responses and each of them an assigned number to ease measuring the SUS.
- Strongly disagree: 1
- Disagree: 2
- Neutral: 3
- Agree: 4
- Strongly agree: 5
For odd-numbered statements like strongly disagree (1), neutral (3) and strongly agree (5), subtract one from the answer.
Let's say the answer to one of the statements was "neutral," the score would be 3 - 1 = 2.
On the other hand, for even-numbered statements such as disagree (2) and agree (4), subtract the answer from 5.
So, if you got a "disagree," the score would be 5 - 2 = 3.
Then, sum up all the points obtained from the answers and use this formula:
SUS = Total amount of points * 2.5
If you got 31 from the answers to your questionnaire, your SUS will be 31 * 2.5 = 77.5
According to UsabilityGeek, your SUS should be above 80.3 to be excellent, while scores under 68 mean you should improve your product's usability.
2. Net Promoter Score (NPS)
Net Promoter Score determines if users are likely to recommend your product on a scale of one to ten.
This key metric is useful to indirectly measure user satisfaction and understand how users perceive their experience.
Based on their responses, you can find:
- Promoters rate their likelihood of recommending the product as nine or ten.
- Passives rate the product with a seven or eight and indicate moderate satisfaction but a low likelihood of recommending the product.
- Detractors rate the product between zero and six and it is a sign of dissatisfaction and a strong likelihood of criticism.
To measure, present and report NPS, you can follow this formula:
NPS = % promoters - % detractors
Here's an example of how to calculate NPS if 122 users rated 0–6, 163 users rated 7–8 and 257 users rated 9–10.
1. Determine the percentage of Promoters following this formula: Promoters/Total Users * 100 = % of Promoters: (25/542) * 100= 47.42%
2. Determine the percentage of Detractors through this formula: Detractors/Total Users * 100 = % of Detractors: (122/542) * 100= 22.51%
3. Calculate the NPS by subtracting the percentage of Detractors from the percentage of Promoters: 47.42% - 22.51% = 25.91%
A positive result (above 0) indicates a positive sentiment and customer loyalty, while a negative one indicates customer dissatisfaction.
3. Customer Satisfaction Score (CSAT)
Customer Satisfaction Score measures how satisfied users are with your product.
By getting customer feedback through a scale of 1 to 5 you can understand their level of satisfaction with their product.
- 1 is very unsatisfied
- 2 is unsatisfied
- 3 is neutral
- 4 is satisfied
- 5 is very satisfied
Once you have the number of satisfied (4) and very satisfied (5) users, you can get the CSAT by dividing the number of satisfied users by the number of participants and multiplying it by 100.
CSAT = (Number of Satisfied Users / Number of Participants) * 100
For example, you get 34 very unsatisfied users(1), 23 unsatisfied (2), 45 satisfied (3), 67 satisfied (4) and 55 very satisfied (5).
You have 224 respondents and 67 and 55 are among satisfied and very satisfied, which total is 122: CSAT = 122/224 × 100 = 54.46%
As a result, 54.46% of users are satisfied with your product.
Conclusion
UX KPIs help teams gather actionable insights to align digital products with user needs, preferences and expectations.
As a UX-driven Product Development agency with over a decade in the market, we know these metrics are key to creating top-notch experiences.
Reach out to hear about our approach!
