Turchin has made contributions to the fields of population ecology, cultural evolution, and historical dynamics. He is one of the founders of cliodynamics, the scientific discipline at the intersection of historical macrosociology, cliometrics, and mathematical modeling of social processes. Turchin developed an original theory explaining how large historical empires evolve by the mechanism of multilevel selection. His research on secular cycles has contributed to our understanding of the collapse of complex societies as has his re-interpretation of Ibn Khaldun's notion of "asabiyya" as "collective solidarity".