Ian Fletcher claims here that "Free Trade Isn't Helping World Poverty," and Don Boudreaux responds here. Here's some related research:
From a 2009 NBER working paper "Parametric Estimations of the World Distribution of Income," by Maxim Pinkovskiy and Xavier Sala-i-Martin (Columbia University):
Abstract: We use a parametric method to estimate the income distribution for 191 countries between 1970 and 2006. We estimate the World Distribution of Income and estimate poverty rates, poverty counts and various measures of income inequality and welfare. Using the official $1/day line, we estimate that world poverty rates have fallen by 80% from 0.268 in 1970 to 0.054 in 2006 (see chart above). The corresponding total number of poor has fallen from 403 million in 1970 to 152 million in 2006. Our estimates of the global poverty count in 2006 are much smaller than found by other researchers. We also find similar reductions in poverty if we use other poverty lines. We find that various measures of global inequality have declined substantially and measures of global welfare increased by somewhere between 128% and 145%. We analyze poverty in various regions.
MP: The bottom chart above shows poverty rates for the five regions analyzed in the paper, with some pretty amazing results for East Asia (includes mainland China, Taiwan and S. Korea), which in 1960 had the highest regional poverty rate in the world by far, at 58.8%, compared to 39.9% for Africa, 11.6% for Latin America, 8.4% for MENA (Middle East, N. Africa) and South Asia (20.1%). In the 36-year period between 1970 and 2006, the poverty rate in East Asia fell to only 1.7% by 2006, which was below any of the other four regions: Africa (31.8%), Latin America (3.1%), MENA (5.2%) and South Asia (2.6%).
Both graphs are based on a poverty measure of $1/day, but the authors obtain similar results using four other measures of poverty from $2 to $10 per day, both for the overall reduction in world poverty (top graph) and the regional differences (bottom graph).
Bottom Line: Assuming these estimates are accurate, the 80% reduction in poverty between 1970 and 2006 has to be the greatest reduction in world poverty in such a short time span in the history of the world, and the 97% reduction in East Asia has to be the most significant improvement in regional standard of living in history as well. The authors don't explore the reasons for the record reduction in world poverty, but some likely candidates might be: globalization, market-based reforms, liberalization, Information Age technology, productivity gains in agriculture, the collapse of central planning in China and India, etc.