The methodology for the 2013 rankings largely corresponds to that used in previous years, which emphasizes the robustness of a region's growth both recently and over time. It allows the rankings to include all of the metropolitan statistical areas (MSAs) for which the Bureau of Labor Statistics reports monthly employment data. They are derived from three-month rolling averages of U.S. Bureau of Labor Statistics "state and area" unadjusted employment data reported from November 2001 to January 2013.
The data reflect the North American Industry Classification System categories, including total nonfarm employment, manufacturing, financial services, business and professional services, educational and health services, information, retail and wholesale trade, transportation and utilities, leisure and hospitality, and government.
This year's rankings use four measures of growth to rank all 398 metro areas for which full data sets were available from the past 10 years. "Large" areas include those with a current nonfarm employment base of at least 450,000 jobs. "Midsize" areas range from 150,000 to 450,000 jobs. "Small" areas have as many as 150,000 jobs. This year’s rankings reflect the current size of each MSA’s employment. Only two MSAs changed size categories, with Honolulu, HI moving from “Midsized” to “Large” and Savannah, GA moving from “Small” to “Midsized.” In the instances where the analysis refers to changes in ranking order within the size categories, these two MSA’s changes are reported as if they had been included in their current category in the prior year.
The index is calculated from a normalized, weighted summary of: 1) recent growth trend: the current and prior year's employment growth rates, with the current year emphasized (two points); 2) mid-term growth: the average annual 2007-2012 growth rate (two points); 3) long-term trend and momentum: the sum of the 2007-2012 and 2001-2006 employment growth rates multiplied by the ratio of the 2001-2006 growth rate over the 2007-2012 growth rate (two points); and 4) current year growth (one point).