A measure which is becoming more widely used is the Net Promoter Score. This measure stems from the premise that a customer's willingness to recommend the company's products and services to their entourage is a valid indicator of loyalty.
This index is interesting for quick determination of trends when results fluctuate, whether such fluctuations are negative or positive. However, this indicator assumes that the customers surveyed will act according to their survey response and actively promote the organization within their entourage when their response is positive.