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:
1. that the population whose behaviour was modeled should be sufficiently large
2. that the population should remain in ignorance of the results of the application of psychohistorical analyses
Well, the second axiom always make me think about the cryptic way Central Bank Governors express themselves, witness this quote by Alan Greenspan when he was Chairman of the Federal Reserve:
Since becoming a central banker, I have learned to mumble with great incoherence. If I seem unduly clear to you, you must have misunderstood what I said. (Speaking to a Senate Committee in 1987, as quoted in the Guardian Weekly, November 4, 2005).
The FOUNDATION cycle by Asimov is really a must read for anybody interested in the potential of social sciences in understanding & forecasting the development of human societies.
As an aside, the ROBOTS cycle is also a foundation of the principles of Artificial Intelligence. Also, I recommend Asimov's THE END OF ETERNITY as it's one of the most clever insights to the consequences time travel would have on history.