Psychohistory uses the current conditions of society to predict its future conditions. Reverse psychohistory looks at the future conditions of society with Chronotech and runs the equations backwards to determine society's current conditions.
Like regular psychohistory, it's a probabilistic science. And you need a lot of temporal bandwidth to make it work. And often, it would be easier to send back the relevant information after checking it in the future. But reverse psychohistory is still quite useful for discovering secret organizations and covert operations, since such things are often very difficult to check.
Even without Chronotech, reverse psychohistory can be used to analyse the past. But that's just history.
Descriptors: Procedure, Infrastructure, Silent
Core Technologies: Metatech 3+, Chronotech 5
PS: Speaking of using Chronotech with existing Metatech, couldn't Chronotech let you skip the research phase for Word-Association Hesitation Induction?