Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This paper shows that improvements in life expectancy (LE) had a non-linear effect on income per capita over the 1940-1980 period as this effect was conditional on each country's initial level of LE. Whereas higher LE had an initial statistically significant negative impact on income per capita in countries with LE under 43 years in 1940, the opposite is true in countries with initial LE over 53 years.