Aardvark

they r not very accurate. no one con judge u with just a single test. But u can try many tests and take a avg of that. it would be much closer to reallity

I don't know much about the Ennegram but I have a bunch of friends that swear by it. I would not say the Ennegram is based on datapoints.

from wikipedia about the Ennegram: his (Gurdjieff's) concept of it was principally related to the symbolic communication of ancient knowledge and the "self-work" process through which people may develop insight rather than the categorizing of personality styles.

Well, considering statistical data points would be the primary scientific way to assess if personality tests are "true," I'm not sure I get the second part of the question. To respond to the first half, though, the Enneagram isn't typically considered a scientifically-valid psychological instrument. Psychologists tend to use measures such as the MMPI, the MCMI, or even the Rorschach ink blot system to assess personality. These are all gauged off of "incremental validity" - that is, how much more can it tell you about a person's personality than you learn with basic demographic information and an hour-or-so long clinical interview? This research has historically measured incremental validity by comparing the psychological ratings a psychologist with these test results comes up with, against ratings they would receive from a spouse, a loved one, or even a psychologist who has worked with her/him for a very long time.

Thanks!