As prof. Murphy states, it certainly does "measure something revelant".

Of the 1000 respondants to his questionair, 65% of the readers of his blog Do the Math fell in the NT category. Yet in a normal population NT profiles represent a mere 10% . So a factor-of-anomaly.

chapter 18.1 Personality, pages 304-308,

https://escholarship.org/uc/energy_ambitions.