"The unprecedented split between growth and living standards is the defining economic agenda of the day," says the EPI's senior economist, Jared Bernstein.
During the five years from 2000 to 2005, the US economy grew in size from $9.8 trillion to $11.2 trillion, an increase in real terms of 14%.
Productivity - the measure of the output of the economy per worker employed - grew even more strongly, by 16.6%.
But over the same period, the median family's income slid by 2.9%, in contrast to the 11.3% gain registered in the second half of the 1990s.
The wages of households of African or Hispanic origin fell even faster.
And new entrants to the labour market fared particularly badly.
Average hourly real wages for both college and high school graduates actually fell between 2000 and 2005, and fewer of the jobs they found carried benefits such as health care or company pensions.