[edsrzf]

Honest question: what science? Any good papers you could recommend?

After a quick search it seems that NPS originated in a Harvard Business Review article, which I don't consider a credible source of scientific results. The scientific papers I'm seeing mostly seem pretty skeptical, judging from the abstracts.

[MrPatan]

They're using the popular meaning of "science": A claim from an impressive or impressive-sounding person or institution.