Harvard economist Raj Chetty: how to improve income mobility

Any starting point that doesn't start with the fixed pie fallacy and focusing on bringing down the rich instead of bringing up the poor, I think, is a good one though I wonder if each party is just looking to for what it wants to hear (WSJ):

In a presidential campaign where candidates from both parties are blaming globalization for a shrinking middle class, a 36-year-old India-born economist has a different explanation: Bad neighborhoods and bad teachers rob poor children of the chance to climb into the middle class.

His solution? Help the children and their families move to better neighborhoods.