Too Long; Didn't Read
How scientific is the five-factor model of personality psychology? On a scale of 1 to 10, where 1 is not scientific at all and 10 is very scientific, I would place the five-factor model at 4. In this case, I use scientific to mean the ability to make useful, reliable predictions. By that standard, IQ, much as some people hate it, is scientific. Astrology, much as some people like it, is not scientific.