METHODOLOGY

To identify the counties where the American dream is dead, 24/7 Wall St. reviewed the effect on household income earned in adulthood for every year of childhood spent in 2,973 U.S. counties from data published by The Equality of Opportunity Project. Researchers at the organization used de-identified data from 1996-2012 tax returns to study the long-term economic outcomes of approximately 50 million children.

This annual effect on adult earnings is called the exposure effect and is measured as the percent gained or lost from the average household income for a 26 year old in the bottom quartile of U.S. earners — $26,090. We calculated the average income lost for each county by multiplying the exposure effect by this national income threshold.

The Equality of Opportunity Project publishes economic mobility-related research and data files for public use. It receives funding from Stanford University, Harvard University, the National Science Foundation, and several charitable groups, including the Robert Wood Johnson Foundation.