The fight in Wisconsin is about power--the power to organize into unions and the power to influence politics. But it is also about money. If Republican governor Scott Walker weren’t claiming that the state’s public workers were wildly overpaid, and if a lot of people weren't inclined to believe him, his proposal to crush the state's public employee unions wouldn’t be on the verge of becoming law.

As an empirical matter, Walker’s claim seems suspect. A new paper by the Economic Policy Institute breaks down the numbers and finds that Wisconsin’s public workers are, if anything, underpaid relative to their private sector counterparts. Of course, Walker and his allies insist that the real problem is not so much wages as health benefits and pensions. But the researcher who wrote the EPI paper, Jeffrey Keefe of Rutgers University, considers that possibility. Although public employees may pay less for some benefits--in particular, their health insurance typically comes with lower premiums and cost-sharing--he argues they still fare no better than their private sector counterparts when it comes to total compensation.

Here's how Keefe's results look graphically, courtesy of economics blogger Menzie Chinn (h/t Michael Tomasky):

Am I certain Keefe is right? No. Having spent some time reporting on public and private sector compensation before, I can tell you that there is a lot of disagreement over the proper way to adjust the raw compensation figures to account for variables like age, education, and so on. (The debate is as much philosophical as methodological: Some conservatives argue that public employers put an artificial premium on graduate education, effectively paying more for degrees that don’t make workers better qualified.) I haven’t seen a specific refutation of Keefe’s report on Wisconsin, but if you want to read an analysis that suggests public workers, in general, are over-compensated, Andrew Biggs of the American Enterprise Institute has done work along those lines--and has a new article in the Weekly Standard summarizing his views.