When I started to work for the US Geological Survey in August 1978, it was known from a study commissioned by then President Carter that federal employees were 20+% underpaid compared to comparable private sector jobs for comparable size organization, companies, state agencies, etc.
That trend continued through all the subsequent presidential administration, all of whom commissioned the same study, some to know and some to try to prevent giving federal employees pay raises. The only benefits for federal employees are job security, which has almost disappeared over the years with changes in the regulations, health insurance, and an average annuity, more the longer you stay up to the maximum of 40 years.
Starting in 1986 federal employees could save additional money with the retirement through the Thrift Savings Plan (TSP), which I did along with many others. While it helped when I retired in December 2005, it didn't help enough under the recent years of the economy and two of the last three years of frozen annuity payments.
But that's wandering. The point is that all the studies commissioned by all the president from Carter through GW Bush have proven that federal employees are underpaid by 20-24% depending on the time of the study. Now the Government Accounting Office (GAO) is saying those studies don't matter as they were not definitive compared to today's salaires.
Well, not that's not true. What has happened is that while federal employees salaries have stagnated by the President Obama and this Congress, private sector salaries have fallen where the 20% difference has almost disappeared. That means while federal employees have suffered, now private sector employees are suffering.
That's not parity, that's suffering. And now private sector workers understand what federal employees have known and lived for over 3 decades now, being underpaid.