What explains differences in life expectancy at age 50? This column looks at the effect of wealth, education, and marital status. It finds that by far the most important factor is education, and explores what this might mean for policy.

Does rising life expectancy boost economic growth? Existing evidence is mixed, with the relationship appearing to change over time. This column presents recent research showing that living longer may have a negative effect on growth to begin with, but once fertility declines the effect becomes significantly positive. Moreover, higher life expectancy increases the probability of such a switch in fertility behaviour.

Public-health interventions in Ireland during the 1940s were successful in dramatically reducing infant mortality. This column argues that in addition to any immediate benefits, they also had long-run effects by improving the health of the adults who were affected as children, especially those from lower socio-economic backgrounds.

In the least 30 years, the difference in life expectancy at birth across the globe has fallen dramatically. This column presents new data on life expectancy within and between countries for the period 1970 to 2000. Controlling for infant mortality, it finds that while within-country inequality in life expectancy fell, between-country inequality rose, leaving total inequality unchanged.

Many healthcare policymakers and analysts are focused on controlling rising medical costs. Is attacking high-cost, low-benefit medical innovation a solution? This column estimates that medical innovation – the use of advanced diagnostic imaging, newer drugs, and higher-ranked physicians – significantly increases life expectancy without raising medical expenditures per capita.

The World Health Organisation recently argued that improving the longevity of the poor is not only an end in itself but also a means to achieving economic development. This column presents contrary evidence from the history of the US.