Asking/testing someone "are you introverted" or "are you extroverted" clearly has at least some categorization value. The criticism is that the categories and t

Asking/testing someone "are you introverted" or "are you extroverted" clearly has at least some categorization value. The criticism is that the categories and testing methods we're not arrived at through any sort of rigorous scientific method. So what you were left with is sort of an arbitrary way to divide people up, resulting in 16 fuzzy final categories. Anecdotally I found it extremely accurate. The first time I visited "my" forum, all of forum avatars were bizarrely from shows and characters that I was close to, the topics were all exactly in line with how I perceive the world, etc. but I'm someone who maxes out all four of the categories in a specific direction. I also have some friends who are blended and have x in parts of their description, so at the end of the day it's sort of an arbitrary classification system, but better than nothing and extremely descriptive for, of course, the people who happen to fit these descriptions.