You're right that the association between unemployment rates and available jobs can be problematic. A 55 year old unemployed office worker from Nevada will not

You're right that the association between unemployment rates and available jobs can be problematic. A 55 year old unemployed office worker from Nevada will not be able to fix fracking equipment in the Bakken Shale. But if the unemployment rate falls to extremely low levels as it has in North Dakota it means that job availability has trickled down from one specific booming industry to basically everything. So there will be a job opening for that 55 year old office worker. Still, it's possible that rents there are sky high and it might not make economic sense to move just to take a job at a burger joint.