Almost everyone agrees there is a gap between federal and private sector wages. But agreement stops over who that gap favors.

Federal unions and the Office of Personnel Management argue that federal wages lag behind civilian pay by about 26 percent.

Now a new USA Today analysis of Bureau of Labor Statistics data concludes feds:

• Earn more than their private sector counterparts in eight out of 10 occupations.

• Earn an average of $7,645 more than similar employees in the private sector.

• Earn benefits worth more than four times those of private sector employees.

(USA Today is owned by the Gannett Co., which also owns Federal Times.)

In truth, pay gaps vary widely based on job requirements and locality. In addition, the federal sector has more senior jobs and fewer junior positions than the typical private sector employer, another factor that can skew the averages.

But the federal wage system is structured to provide rapid pay increases that aren't typically matched in the civilian sector, where employees often have to switch employers to earn bigger raises or promotions. For many feds, annual raises come in addition to annual step or grade increases, and these are mostly automatic; in the private sector, salary increases are almost always tied to performance and promotions, rather than longevity.

The debate is not merely academic. Concern over federal pay is gathering steam. The issue helped Massachussetts Sen. Scott Brown get elected in January. And last week, Rep. Joe Barton, R-Texas, launched an investigation into the number of employees earning more than $100,000 at nine federal agencies.

One factor working against feds is that the official pay gap estimates don't pass the smell test. Officially, the government contends that private-sector employees are getting paid 48 percent more than feds in Atlanta, 56 percent more in Boston, 61 percent more in New York and 68 percent more in Washington. Those differences are so extreme it's hard to believe these positions can be filled at all. Making matters worse, the methodology to calculate these pay gaps is unintelligible, and largely hidden from view.

What's needed is a thorough, transparent, and independent review that provides a more detailed and nuanced understanding of where the pay gaps are throughout government.

Once that is accomplished, lawmakers and the administration can set about fixing the wrongs — raising the pay for those who aren't getting a competitive wage, and reducing starting salaries and future raises for positions where the federal sector is more generous than it needs to be.