Isaac Asimov, one of the masters of Anticipation, aka Sci-Fi, invented the concept of Psychohistory in his novel FOUNDATION (1951). Well, I believe what psychohistory is really describing is (macro)econometrics when it works perfectly, if it ever does.
Indeed, if I quote wikipedia's description of psychohistory, it relies on the following axioms:
Psychohistory depends on the idea that, while one cannot foresee the actions of a particular individual, the laws of statistics as applied to large groups of people could predict the general flow of future events. [...]
Asimov applied this concept to the population of his fictional Galactic Empire, which numbered a quintillion. The character responsible for the science's creation, Hari Seldon, established two axioms:...