How to rate usability and user loyalty?

Hello fellow UX’rs!
This week I want to share with you a little introduction to measuring loyalty and usability of websites with 3 different scales:
Net PromoterSysten Usability Scale (SUS) and the Standardized Universal Percentile Rank Questionary (SUPR-Q).
All this three measuring tools are design to get an insight on how the users perceive the website or system. They all have their own advantages and flaws.
My main idea with this post is to give an introduction to them.

Net Promote Score

The year: 1993

Fred Riechheld introduces the Net Promote Score. A simple and intuitive way to measure the likeliness of the costumers to recommend the company to others. An easy way to know about costumer loyalty.
This scale is intuitive and easy to understand, it consist of only one question:
How likely are you to recommend this website to a friend or a colleague?
And the user is presented with a scale from 0 to 10, with 0 being Not at all likely and 10 Extremely likely.
To calculate the results, one has to take the Promoters minus the detractors.
Promoters are those that select 9 or 10. Detractors are those that choose 0 to 6. 7 and 8 are neutral.
Net Promoter, NPS, and Net Promoter Score are trademarks of Satmetrix Systems, Inc., Bain & Company, and Fred Reichheld.

SUS (System Usability Scale)

Developed by John Brooke in the 1980′s, it consist of 10 simple questions:
  1. I think that I would like to use this system frequently.
  2. I found the system unnecessarily complex.
  3. I thought the system was easy to use.
  4. I think that I would need the support of a technical person to be able to use this system.
  5. I found the various functions in this system were well integrated.
  6. I thought there was too much inconsistency in this system.
  7. I would imagine that most people would learn to use this system very quickly.
  8. I found the system very cumbersome to use.
  9. I felt very confident using the system.
  10. I needed to learn a lot of things before I could get going with this system.

The user can rate the results on a scale from 1 to 5, with 1 being “Strongly Disagree” and 5 “Strongly Agree”
All odd questions are “positive” and even questions are “negative”
A response of 5 on the first question means the user likes the website. But a response of 5 on the second questions implies that he/she finds the website too complex.
To get a reliable way to measure, one has to do the following:
For all odd questions, subtract one: this will give a result from 0 to 4.
For all even questions things get more tricky… one has to look for the difference between the result and 5: if the answer is 3, the final result will be 2 (5-3=2) If the result is 5 the result is 0 and for 1, the result is 4.
Once all the answers have been properly formatted, they are added and multiplied by 2.5, to get a result from 0 to 100.
Jeff Sauro, from Meassuring Usability shares his findings on what is a good result. 68 is the average. Anything above is good, and anything under is bad. He also indicates that SUS results are not percentages.
The previous stated 68 will be something around 50%.
When it comes to websites, things can be a little different. For example, as Sauro comments, question number 4 could not be applicable to websites (I think that I would need the support of a technical person to be able to use this system), due to their nature. My opinion (and this is only my opinion) is that users could find themselves looking for the help or FAQ of some websites at some point. Also, there are systems out there, such as commerce or heavy duty web applications that will require the user to follow a step learning curve, and in some cases, contact tech support.

The Standardized Universal Percentile Rank Questionary

The last questionary I want to talk about is the Standardized Universal Percentile Rank Questionary (SUPR-Q).
This questionary is divided into 4 different categories.
The questions on the first category are about usability:
1 – This website is easy to use
2 - I am able to find what I need quickly on this website
3 - I enjoy using the website
4 - It is easy to navigate within the website
The second category deals with Credibility
5 - I feel comfortable purchasing from this website
6 - This website keeps the promises it makes to me
7 - I can count on the information I get on this website
8 - I feel confident conducting business with this website
9 - The information on this website is valuable
Third category is about Loyalty
10 - How likely are you to recommend this website to a friend or colleague? (same question as the Net Promoter Score)
11 - I will likely visit this website in the future
The appearance of the site is the topic for the last category:
12 - I find the webs tie to be attractive
13 - The website has a clean and simple presentation
As with the SUS, all the question have a 1 to 5 score system except for question 10 which is from 0 to 10.
All this set of questions are trademark, and one needs to buy a license.
For SUPR-Q and SUS, Jeff Sauro has excellent platforms that one can buy from his website “Measuring Usability“. He has posted some videos on YouTube about how the platform works, for both the SUS and SUPR-Q.
For the Net Promote Score one can find resources at
Well, this is all for this week, hope you get something to use from all this information.
If I have any mistake / error, please, feel free to contact me.
Lucas Wxyz

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