The science of harnessing customer loyalty and satisfaction is getting very trendy in business. And perhaps nothing has been more responsible for driving excitement than Net Promoter.

Developed by Fred Reichheld, Net Promoter is a loyalty metric and a discipline for using customer feedback to support business growth and profitability. You’re probably familiar with the ubiquitous Net Promoter question, “On a scale of zero to 10, how likely is it that you would recommend our company to a friend or colleague?”

The basic idea is that you can use that question to segment your customers into three core groups: Promoters (scoring 9–10), Passives (7–8), and Detractors (0–6). You derive your Net Promoter Score (NPS) by subtracting the percentage of Detractors from the percentage of Promoters. The higher the score the better.

While the model has stirred some controversy, NPS proponents—including many prominent business leaders—claim this is a simple and effective framework to measure company performance, customer satisfaction, and loyalty. It’s gritty and actionable for frontline employees across business divisions, while insightful and predictive for management.

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