It's also important to remember that it includes the neighborhoods you may not be so excited to live in where rents are going to be cheaper, driving down the average. I live in Chicago, my "living wage" is like $85,000/yr for a single guy with no kids, but my area also has a median rent of >$2000 and I need a 2nd bedroom to use as an office.

This stuff is so general as to be basically worthless beyond a comparison between areas, not as a datapoint to use when calculating the cost of living somewhere.