Differences in wages between federal employees and similar private-sector employees in the 2005-2010 period varied widely depending on the employees’ level of education.
Federal civilian workers with no more than a high school education earned about 21 percent more, on average, than similar workers in the private sector.
Workers whose highest level of education was a bachelor’s degree earned roughly the same hourly wages, on average, in both the federal government and the private sector.
Federal workers with a professional degree or doctorate earned about 23 percent less, on average, than their private-sector counterparts.
Overall, the federal government paid 2 percent more in total wages than it would have if average wages had been comparable with those in the private sector, after accounting for certain observable characteristics of workers.
via Congressional Budget Office – Comparing the Compensation of Federal and Private-Sector Employees.