Slashdot today ran a piece about the U.S. Government paying its own programmers half the going rate for contract programmers. The comments, at least early-on when I read them, tended to focus on the premise that contract programmers are paid extra to, well, go away on short notice. (I've worked as a "temp"--high-tech flunkie as well as office minion--and, frankly, I have no idea where that notion comes from, at least not if a temp. agency is involved.)
Me, I'd tend to place the discrepancy at the intersection of hiring freezes and the spend-it-or-have-your-budget-slashed-next-year school of fiscal "management" that I've seen in the private sector as well.
But speculation, however plausibly grounded in past experience is not the point. Combine nerdy quirkiness and stupefying levels of through-the-looking-glass bureaucratic "logic," and the reasons could well fall outside the pale of our workaday norms. The most likely of those, to my way of thinking, include:
1.) Well, duh: People from the outside are always smarter
2.) Legendary public sector "job security" includes cubicle in lead-lined bunker and cryogenic suspension in the event of thermonuclear Armageddon
3.) Pay comparison doesn't take into account standard government-issue solid gold laptops
4.) Coders willing to take lower pay to develop "secret government technology" cachet irresistable to fellow geeks of the preferred gender
5.) Pay differences easily offset by illegal kickbacks from soda and energy drink vendors
6.) Former college interns didn't notice the "indentured servitude" clause in their NDAs
7.) Government I/T departments are the digital tar-pits where old COBOL and VB6 programmers go to die
8.) Uncle Sam's coders are rented out as cheap off-planet labor for our secret extraterrestrial allies--and neural implants don't grow on trees, you know
9.) Daily flogging and haranguing by Grover Norquist & Tea Party to destroy self-worth
10.) Once-in-a-lifetime chance to hack Andrews Air Force Base and take Air Force One out for a joyride