Jack Goldstone writes that the fastest population growth is coming from the world’s poorest and worst-governed countries.

Next week, according to United Nations projections, the world will pass 7 billion in population, and by the end of this century it’s likely to grow by half again to 10 billion.

What will determine their quality of life? From an economist’s view, what matters is the productivity of the 10 billion—will they be educated and have jobs that contribute to economic growth?  From a sociologist’s view, what matters is whether the 10 billion are socialized into stable roles in society—can they build families and join communities where they have dignity and focus on building for the future? From a political scientist’s view, what matters is the quality of government in countries where most of the 10 billion will live—will those governments avoid corruption, enforce the rule of law, and protect participation and civil rights?