Making Sense of SUS Data

Making Sense of SUS Data

If your customers can't use your app or website easily, they'll simply move on to the next one. And they won't think twice about it.

That's why usability is so important. And that's why making use of the System Usability Scale, or SUS, is a smart idea for any product developer.

The question is, what exactly does all of the information you get with the SUS mean? How does it affect your business?

Here's a rundown on the SUS data you'll get from using a top-tier assessment tool, and how to use this information.

Let's get started!

SUS Score

This score represents how usable and learnable your website or other offering is. Note that 68 is the average SUS score.

That means if your SUS score is above 68, the score is above average. On the flip side, if the score is under 68, it is below average.

A score of 75 is better than about 73% of SUS scores. Meanwhile, a score of 52 is worse than around 85% of scores.


This score represents whether a user would need a technical person's support to be capable of using your offering. The score also represents whether a user would need to learn a large amount of information before starting to use your offering.

Note that your learnability score will usually track higher than your usability store (more on that next) and your overall SUS score.


This score refers to how easy it is for a user to make use of your tool. How efficiently can users use your offering to accomplish their specific objectives both effectively and satisfactorily?

Standard Deviation

The standard deviation shows how much variation there is in your score from the average SUS score.

If your standard deviation figure is low, this means that the data are close to the average. Meanwhile, if your standard deviation is high, this means that the values are instead spread out over a much wider range.

Cronbach's Alpha

This figure refers to how reliable your data are. In other words, it lets you know how much your score will be consistent from one time to the next.

Adjective Average

This part of your data results provides you with a word rather than a number to describe the user experience. Any score above 85 is "Excellent," whereas "Good" is slightly above average.

In addition, any score at 51 is "OK."

Net Promoter Score

This score tells you how willing your customers are to recommend your offering to other people. How satisfied is the user overall with your product on a scale of -100 to 100? This information will tell you how loyal they are to your company's brand.

How We Can Help

We offer an excellent tool that will provide you with clearer insight into how you can measure usability at your company.

We take pride in this tool because we know that it can help you to control your costs as well as optimize your resources. In the end, you can deliver even better offerings for your customers.

As soon as you sign up, you can quickly and easily complete your SUS test.

Our two plans offer a slew of beneficial resources, such as unlimited tests, analytics built in, and co-branding.

Also see

System Usability Scale (SUS) Plus

Free tool

Conducting SUS evaluation offline? Create print-ready questionnaire for your participants with our SUS PDF generator.

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