Countries that are wealthy, have less income inequality, and whose citizens have the highest educational levels are the most likely to develop universal health care systems, according to new research from Harvard School of Public Health (HSPH). The study also found that countries run by dictators or those with high levels of ethnic fractionalization are less likely than others to implement universal health care.

The new findings are part of a comprehensive analysis by first author Andrea Feigl, a doctoral candidate in...