You might think that the kind of extreme poverty that would concern a global organization like the United Nations has long vanished in this country. Yet the special rapporteur on extreme poverty and human rights, Philip Alston, recently made and reported on an investigative tour of the United States.

Surely no one in the United States today is as poor as a poor person in Ethiopia or Nepal? As it happens, making such comparisons has recently become much easier. The World Bank decided in October to include high-income countries in its global estimates of people living in poverty. We can now make direct comparisons between the United States and poor countries.

Properly interpreted, the numbers suggest that the United Nations has a point — and the United States has an urgent problem. They also suggest that we might rethink how we assist the poor through our own giving.

According to the World Bank, 769 million people lived on less than $1.90 a day in 2013; they are […]