In my last post, in the wake of Michigan’s addition to the ranks of right-to-work states, I showed how hard it is to attribute a state’s union strength to its right-to-work status. But what about wages? Can right-to-work’s effect be seen in how much union and nonunion workers earn in a given state? There’s a lot to go through here, so let’s get right to it.

Once again, I’m focusing on Oklahoma, because of its 2001 adoption of right-to-work, and gauging how its performance compares with those of the 49 other states over the ensuing decade.

In 2001, Oklahoma workers who were union members earned, on average, 24.4 percent more than those who weren’t. After 10 years as a right-to-work state, that gap had shrunk to 19.5 percent in 2011.

But that’s not so special. Between 2001 and 2011, the gap between union and nonunion earnings narrowed in exactly half of the 50 states. Of these 25 states, 15 saw their union wage advantage shrink even more rapidly than Oklahoma’s—and the majority of them were not right-to-work states.

Dollar for dollar, earnings for union workers actually grew in Oklahoma over the past decade—and by a relatively healthy amount, too. The average hourly earnings for union workers in the state increased 7.4 percent from 2001 to 2011 (in 2011 dollars). Only 11 states saw a greater jump in union earnings, while 21 states experienced a smaller jump, and 17 states experienced an earnings decline for union members. The right-to-work states are all over the map when it comes to union earnings: five of them saw a greater increase than Oklahoma’s, 10 saw a smaller increase, and six saw a net decrease.

How did nonunion workers do? In Oklahoma, they fared even better than their union counterparts: The state posted an 11.7 percent increase in average hourly earnings for nonunion workers from 2001 to 2011 (in 2011 dollars). That’s better than all but five other states. But it would be difficult to claim that this surge came at the expense of union workers, given Oklahoma’s top-level union wage increases. Meanwhile, nine states saw a decline in nonunion earnings, and the rest saw a more modest increase than Oklahoma’s. Once again, the right-to-work states were scattered proportionately among all three groups.

Perhaps the most conclusive statistic I unearthed on the inconclusiveness of right-to-work’s impact on workers’ paychecks is this: From 2001 to 2011, union workers fared better, earnings-wise, than nonunion workers in exactly half of the 22 right-to-work states, and nonunion workers fared better in the other half. What’s more, this symmetry held true for the nation as a whole: Union workers gained more (or, in some cases, lost less) than nonunion workers in 24 states over the past decade, while nonunion workers had the upper hand in 25 states.