I've seen the elephant curve in more than a few news stories about inequality. The curve suggests that while income growth has been strong in middle-income countries, income growth for the poor to middle class in rich countries has been very weak.
The Resolution Foundation dug into things and found that the trough is mostly dismal performance among former Soviet economies and Japan, with population growth and countries transitioning from fast growing developing countries into slower mature ones also playing a role.
Here's Resolution's Head of Research's tl;dr:
Tl;dr - population growth in EMs means a compositional effect which pulls down income around 80th percentile. pic.twitter.com/XdGcW3vvIG— Duncan Weldon (@DuncanWeldon) September 13, 2016
Meanwhile, growth in household incomes in New Zealand remains broadly shared.Tl;dr 2: yes, Chinese & emerging middle class are the big winners of globalisation. But western low/middle earners aren't really losers.— Duncan Weldon (@DuncanWeldon) September 13, 2016