"Net Promoter Score" can only be measured by survey, because that's exactly what it is. It's a 1-question survey with a standardized scoring methodology that is

"Net Promoter Score" can only be measured by survey, because that's exactly what it is. It's a 1-question survey with a standardized scoring methodology that is a de-facto standard measure of customer loyalty across industries. If you want to measure customer loyalty and quantify it for investors, you can use that methodology, or you can find another way but call it something else. I wouldn't recommend doing something else and trying to call it NPS.