Apples and Oranges - a Problem for NPS

I think we have been missing the mark when we use NPS as a critical measurement for customer satisfaction. The challenge to this metric is that it appears to be combining "apples and oranges". The metric is defined as the difference between attractors and detractors. That is the problem!

What makes this an apples and oranges metric is that we are combining two different characteristics. The assumption in the NPS metric is that attractors and detractors are measured on the same scale. If attractors are apples and detractors are oranges, you can't subtract oranges from apples. Let me expand on this notion in the following paragraphs.

According to the literature, attractors characterize satisfaction. It carries with it the notion that attractors represent aspects of the product or service that encourages the customer to continue using the product or service because the customer is satisfied. Further, detractors characterize dissatisfaction. Dissatisfaction represents some aspect or aspects of the product or service that has a negative influence on the customer.

Here is the problem. Satisfaction is not the opposite of dissatisfaction.  A low satisfaction score may lead to indifference.  As satisfaction scores drop satisfaction does not directly lead to dissatisfaction.  Nor is dissatisfaction the opposite of satisfaction for the same reasons. Another way of saying this is that dissatisfaction is not the absence of satisfaction, and satisfaction is not the absence of dissatisfaction. Each of these terms, satisfaction, and dissatisfaction, have separate scales that may have the same number of items (such as 0 to 10). You can have a scale of 0 to 10 for satisfiers and a complementary scale of 0 to 10 for dissatisfiers. The current assumption for NPS  that the units of satisfaction are the same as units of dissatisfaction. An example of this is a one-unit positive movement of satisfaction that is assumed to be identical to a one-unit negative movement of dissatisfaction.

Consider an example of a customer who purchases at McDonald's. McDonald's uses a business model that focuses on providing food quickly (it is a fast-food restaurant) and consistent quality (although it may not be the highest quality), it is designed to provide consistency for food quality). Customers would have levels of satisfaction for speed of service and quality of food. And the scale for each could be from 0 to 10. Another component of the service experience of the customer might include using the restroom facility. The restroom facility does not have a satisfaction component. Customers don't usually seek out McDonald's for the quality of the restrooms. The restrooms are considered a convenience for customers rather than a satisfier (a feature that would encourage customers to return). The restroom scale would act as a dissatisfaction scale. It does not add to the satisfaction of the customer experience.  The restroom may use a dissatisfaction scale from 0 to 10. In this case, 10 would indicate no dissatisfaction and zero would indicate complete dissatisfaction.

When we put this customer experience in perspective we see satisfiers (apples) and dissatisfiers (oranges).  A simple question might be whether one unit on the satisfaction scale is equivalent to one unit on the dissatisfaction scale.

I hypothesize that satisfiers and dissatisfiers have different scale values. Hence the assumption that the scale for satisfaction and dissatisfaction used by NPS is equivalent is most likely not true. Customers do not stop going to McDonald's if the service is slow or the quality of food is not as good as usual. Customers will most likely stop going to McDonald's if the restrooms do not appear sanitary.  Thus dissatisfiers may act significantly different than satisfiers. 

The bottom line is that the use of the NPS metric gives a distorted view of the customer relationship.  It is based on the faulty assumption that satisfaction and dissatisfaction are equivalent and can to be measured on the same scale.  Companies that use this metric are likely to be misled about the quality of the relationship with their customers by making decisions based on this metric. It's time that we provide a metric that legitimately considers satisfiers differently than dissatisfiers.