Using a NPS (Net Promoter Score) to judge the health of your organization is deeply flawed and could lead you to thinking you're doing better than you actually are.
It doesn't take into account people who didn't answer the survey at all. Those folks are either detractors or passives.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko