Net Promoter Score (NPS)

NPS (Net Promoter Score) measures customer loyalty by asking how likely someone is to recommend a brand on a 0-10 scale, then subtracting the percentage of detractors (0-6) from the percentage of promoters (9-10) to produce a score from -100 to +100. Developed by Fred Reichheld and Bain & Company, it is widely used as a single, trackable read on loyalty and a leading indicator of retention and growth. Its credibility depends on acting on the follow-up why — Bain's Net Promoter 3.0 pushes teams to tie scores to actual earned growth rather than treat the number as a vanity metric. It is a signal to investigate, not a verdict on its own.

Source: bain.com