The report uses two metrics of economic mobility: absolute mobility, and relative mobility. Relative mobility is unitless because it's an elasticity: it measure

The report uses two metrics of economic mobility: absolute mobility, and relative mobility. Relative mobility is unitless because it's an elasticity: it measures how much parent income influences children income. This is from note 13 in the report. Also, the authors didn't come up with this themselves. The data comes from here: http://www.iza.org/en/webcontent/publications/papers/viewAbstract?dp_id=1993 http://www.iza.org/en/webcontent/publications/papers/viewAbs... This explains nicely where the use of elasticity comes from. Do you have other data that contradicts these conclusions?