The founder of the method is Frederic Reicheld, who first announced the method in the article The One Number You Need to
Grow, published in Harvard Business Review in December 2003. In 2006, he released a book entitled
The Ultimate Question: Driving Good Profits and True Growth.
Link to the article “The One Number You Need to Grow”: https://hbr.org/2003/12/the-one-number-you-need-to-grow
Description of the system: https://en.wikipedia.org/wiki/Net_Promoter
Net Promoter Score this is just a concept and you can use it at your discretion.
Specifically to determine the degree of customer loyalty to your project, the NPS index was created. What is the NPS customer loyalty index?
The Customer Loyalty Index (NPS) (Net Promoter Score) is a metric that companies use to determine the attitude of their customers.
Companies with high NPS have more opportunities to grow and make a profit in the long term.
To calculate the NPS index, you need to conduct a simple survey of your customers. The survey consists of one question:
How likely would you advise this company to a friend?
The answers are based on a ten-point scale.