It wasn't so much Chinese, Indian or Ottoman incomes that diverged from the west's, rather western incomes diverged from everyone else's. When and why that came about is probably the biggest issue in economic history, though Ken Pomeranz's famous identification of the second half of the 18th century as the tipping-point has come in for considerable criticism and economic historians are increasingly inclined to see the beginnings of western Europe's quantitative lead as earlier and less rooted in modern industrialisation or overseas commercial predation.

To put it bluntly, there just isn't the per capita growth in leading western incomes before the 19th century to allow for a late divergence from conditions of real-income parity with more distant lands or (in more gung-ho versions) European backwardness, even allowing for higher rates than those commonly proposed. There are, on the other hand, plenty of indicators - agricultural productivity (a crucial constraint on growth and essential to the development of producers for and consumers of other goods and services), urbanisation, trade and industry itself - to put northwestern Europe ahead of most of Asia well before 1700.

The Ottoman lands however do offer a challenge in their high urban population share, still seemingly rivalling Europe as a whole in the 17th century and possibly through the 18th: on this showing, the empire occupied an intermediate position economically as well as geographically between Europe and the greater part of Asia, and felt the impact of western growth later, perhaps not until the 19th century when Pamuk (The Ottoman Empire and European capitalism) finds a decline of 90% in cotton handspinning and 30% in handloom weaving, though woollens fared batter.

There really isn't conclusive evidence for the movement of Ottoman national income during Europe's industrialisation period. While some sectors suffered in the face of western factory competition, the phenomenon was by no means universal, agriculture responding to the general increase in trade and westerm demand for "Mediterranean" produce. Pamuk finds rising urban real wages from the late 18th century, though he acknowledges that these may be unrepresentative and his estimate for Ottoman GDP c.1820 falls below his figures for the most prosperous European countries three centuries earlier.

Despite setbacks to local industry, there seems no evidence for 18th- or 19th-century Ottoman economic collapse, suggesting that a western lead existed already in the 16th century and perhaps earlier, though there seems no reason to consider it overwhelming and the empire or at least its better-performing provinces and sectors maintained a degree of economic dynamism until its undoing after 1914.