The January state level unemployment figures came out today. The rates range from 3.7% in Wyoming to 11.6% in Michigan.
Over at Carpe Diem, my friend Mark Perry correctly points out that the 8 states with the lowest unemployment rates are all "right to work" states.
But that's not really the whole story. There are data for 50 states plus DC and there are 22 right to work states. We'd want, at a minimum to know, if right to work states have significantly lower unemployment rates than the others.
A couple minutes of slaving over EVIEWS produced the following simple regression
State Unemployment = 7.631 - 0.990*Right to work State
While this says that right to work states have about 1% point less unemployment on average, the t-statistic testing the null hypothesis that the coefficient on the right to work state variable is actually zero is computed to be -1.935. Thus we cannot reject that there is no difference between right to work and non right to work states at the traditional 5% significance level (though we could at the 10% significance level). If we adjust the standard errors for heteroskedasticity the t-statistic falls to -1.87 but the inference remains the same.
If we add an additional dummy variable for the 4 states hit hardest by the foreclosure crisis (California, Arizona, Nevada, and Florida (three of which are right to work states)) we get this:
State Unemployment = 7.47 - 1.183*Right to work State + 1.557*Foreclosure crisis State
In this case both the right to work coefficient and the foreclosure crisis coefficient are significantly different from zero at the 5% level.
So at the simple level of differences between means, there is no significant difference in current unemployment rates between right to work and non right to work states. Multiple regression may reveal a different picture. Of course in all these cases, without a theoretical model behind it, the results are only correlations and can't really be taken as anything causal.