Here's how we ranked the economies of America's biggest cities

• To look closer at the US economy as it varies by metro area, we looked at five measures of economic health.
• We used those measures to establish to ranking of the 40 biggest metro areas in the US.
• Cities such as San Francisco and Seattle have some of the strongest economies; cities like Providence and Cleveland have some of the weakest.
• See the full ranking.

In our ranking of the economies of the 40 biggest metro areas in the US, we looked at five measures of economic health.

Each measure was rescaled to allow us to compare them to one another. Technically, we calculated z-scores for each metro area on each measure, which rescales each variable based on its average and standard deviation.

To make the combined ranking, we added together the five indicator z-scores for each metro area to create an overall economic index.

Here are the sources for each of our measures:

• February 2018 unemployment rate: The most recent unemployment rate for the country's metropolitan areas came from the Bureau of Labor Statistics' Local Area Unemployment Statistics program.
• Year-over-year percent job growth rate between February 2017 and February 2018: Non-farm payroll employment figures were from the BLS' State and Metro Area Employment, Hours, and Earnings program.
• Q3 2017 average hourly wage: The BLS' Quarterly Census of Employment and Wages program tallied this figure.
• 2016 per capita gross domestic product: The Bureau of Economic Analysis releases annual figures on GDP for the nation's metropolitan areas, and we combined that with the Census Bureau's 2016 population estimates to get a per capita figure.
• 2016 GDP growth rate: This also came from the BEA's annual metropolitan area GDP release, linked above.

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