Peter Turchin, a researcher who developed 'Structural-Demographic Theory.'
His theory tracks long historical cycles and the idea of 'elite overproduction' — too many people competing for too few top positions — as a driver of instability.
The description names his core tools: secular (long-wave) cycles, elite overproduction, and a mathematical bifurcation model, but gives no further detail.
His framework is a way to forecast social upheaval from measurable population and elite trends. The write-up here is thin, so this is just a short pointer to who he is.