Companies should follow these seven principles when calculating NPS:

1. Ask the Ultimate Question and very little else
2. Choose a feedback scale that works and stick to it
3. Aim for high response rates from the right customers
4. Report relationship data as frequently as financial data
5. Use granular data to make employees more accountable
6. Audit to ensure accuracy and freedom from bias
7. Validate that scores link to behaviors

If organizations take seriously the goal of turning customers into promoters, then they must take seriously the need to measure their success. As these rules of measurement become more widely practiced, the hope is that they will evolve into a set of generally accepted relationship measurement principles that can focus organizational energy on relationship quality in the same way that the science of accounting has focused us on profits. Over time, indeed, more and more investors and board members may come to demand an audited set of relationship metrics that accord with the rules of measurement detailed in The Ultimate Question.

One's initial impulse may be to balk at the investment required to generate solid NPS metrics, but consider how much most organizations now spend tracking and auditing accounting profits, which can provide only a look in the rear-view mirror. Net Promoter Scores not only help companies see the future, they help them manage it to improve performance. NPS can show companies how to grow.