Research shows that America's claim of social mobility is a myth, according to Harvard Economics Professor Raj Chetty, who told Boston Public Radio Friday that children in America are half as likely to climb out of poverty than they are in Canada.

Chetty is the William A. Ackman Professor of Economics at Harvard and director of the Opportunity Insights program, where his team has determined that geography is crucial in determining social mobility. And this geography is specific, Chetty's research shows — sometimes even correlated to a person's neighborhood or block.

"In Boston, there are sharply different chances of escaping poverty depending on where you're growing up," he said. "There are parts of Dorchester that are higher poverty neighborhoods, where kids, as you might expect, have a poor prospect of climbing out of poverty, but then there are other parts within Dorchester, like Savin Hill for example, where you see kids growing up in low-income families there have really great chances of succeeding."

Chetty set out to determine what causes those disparities. His team piloted a program in Seattle that provided financial and other incentives to encourage more poor families to relocate to what they called "high opportunity" areas — neighborhoods that have been identified as places where low-income children have grown up to have higher earnings, more college degrees and fewer teen births.

"We spend a ton of money in the U.S. government on affordable housing programs to try to give people access in these neighborhoods," said Chetty. "But here's the puzzle: You find even when families get this rental assistance, 80 percent of them are still living in high-poverty, low-opportunity areas where we think their kids are not going to break out of that cycle of poverty across generations."

So the team told families about these high-opportunity neighborhoods, connected them with landlords and simplified the housing voucher process so landlords would be less hesitant to rent to people using them. So far, Chetty said, it's working.