The Net Promoter Score (NPS) is a metric used to gauge customer satisfaction and loyalty. It is based on responses to a single question - "How likely are you to recommend our company/product/service to a friend or colleague?" Respondents are categorized as Promoters (score 9-10), Passives (score 7-8), or Detractors (score 0-6). The NPS is the percentage of Promoters minus the percentage of Detractors. While a simple metric, NPS provides insights when measured continuously over time. Companies should focus on converting Detractors to Passives and increasing Promoters to improve their NPS.