They don’t measure how good your service is. Or how optimal your product is.
They measure how well you did compared to expectations. They measure how well people rank you in the survey.
They’re not the same.
Doing things right is important. Setting expectations is even more important–if your goal is to spread the word.
The Conference Board of Canada just released a detaled study that showed that British Columbia has the best (by objective measures) health care system in Canada. It also reported that BC ranks among the lowest in customer satisfaction.
Not impossible, when you think about it.