Michael Mandel, president of South Mountain Economics and former chief economist at BusinessWeek, has conducted an interesting new study about job growth. Using data from LinkedIn, he found that, "the most connected metro regions had more than double the job growth of the least-connected metro areas.” Does that mean networking leads to more economic activity and more jobs? Not necessarily. Correlation does not equal causation. Perhaps, a high growth economy in a region causes professionals to connect with one another more often. The chart to the left summarizes Mandel's findings.