Historical GDP Back-Projection

Historical GDP back-projection estimates long-run income for periods too thinly documented for full national accounting. Rather than rebuilding sectoral value-added year by year, it anchors to a handful of relatively secure benchmark estimates and fills the gaps between and before them using indirect indicators that move with income, chiefly the share of population living in towns, real wages of building labourers, agricultural productivity, and population density. The logic, associated above all with Angus Maddison and developed further by Allen, Malanima, and van Zanden, is that these indicators bear a stable, theoretically grounded relationship to per-capita output, so their movements can proxy GDP growth where direct measurement is impossible. The method has produced the multi-century per-capita income series that frame debates about pre-modern stagnation, Malthusian dynamics, and the European Little Divergence, while remaining explicitly more uncertain than bottom-up accounts.