[A] model with only a few simple parameters was incredibly good at fitting the genuine growth and evolution of complex societies over 3,000 years. More quantitatively about two thirds of the variation spatially in ‘imperial density’ can be accounted for by the spread and emergence of military technology and the ruggedness of the landscape.From here citing Turchin, et al., "War, space, and the evolution of Old World complex societies" (September 23, 2013).
My intuition from similar studies of this type is that one or two measures of climate history, probably followed in turn by diffusion of agricultural technology, would add the most to the predictive value and chronological range of the model.
The fact that models like this can come reasonably close to the actual course of human history also supports my general tendency to see the broad coarse of human history as largely the deterministic result of technological advances and natural conditions, which in turn drive economic forces, which in turn drive cultural and political developments.
This economic determinism school of historical causation is at odds with the view that history is largely driven by the unpredictable decisions of "Great Men" in history who actually ended up being the proximate cause of what people did at key moments in history. I see circumstances as driving decisions far more powerfully than I see people creating they key circumstances (with the possible exception of inventors, although their discoveries too are far more driven by circumstances and what is natural to investigate given what has come before them than is frequently acknowledged).