Net promoter score in user experience


In lot of websites, you maybe encountered the question "How likely are you to recommend this website to a friend?". This is the question behind NPS.
Net promoter score, or NPS, is a loyalty metric that can be correlated well with user experience. Although it has limitations, it is very easy to understand and reproduce.

Calculation of NPS
NPM is calculated by asking personas to provide an answer, on a scale from 0 to 10.
Then, we have to group this answers in 3 groups:

  • Promoters: Responses of 9 or 10. This indicates a very good satisfaction, and strong likelihood of recommendation.
  • Detractors: Responses from 0 to 6. This indicates dissatisfaction.
  • Passives: Responses of 7 or 8. This indicates moderate satisfaction.

The following image shows the calculation of NPS:

NPS calculation NNgroup

Calculation of NPS, reference:

The passives are included in the total of respondents, but do not contribute to the final score. The rationale is that these users may feel that their needs are fulfilled, but will not actively promote the product or service with family or friends.

Raters tend to be generous and give high scores, because of that, the midpoint is not 5, it is 6.

NPS is easy to collect, it is based on a single question, so users will be more likely to actually respond to that one question than to a lengthy survey.

As a result, it’s become customary to include the NPS in user interviews, surveys, or even usability-testing sessions. UX practitioners often use it as a tool to promote buy-in from their company’s senior leadership.

NPS tells you how your site is working but not why. It does not capture all the problem, only the first part of it.
NPS is only relevant with a large sample size.. Maybe you need hundred of answers to have a valid data to detect a problem.

NPS is simple to administer and understand. You can use tools like Hotjar to collect data from your users. However, remember that it is a subjective metric. Do not use in isolation, combined with another UX metrics, NPS has very useful.