@Bertrand I think it basically says that 93 to 97% of the variance of sociotype behaviour can be explained by the four primary dichotomies (E\I, N\S, T\F, P\J) or the eight IMs, and thus all other dichotomies are significantly less efficient and reliable for typing purposes. As a lesser point, the P\J dichotomy is significantly less helpful than the other three primary dichotomies.