Living Green: About the Methodology

How we determined the world's greenest, most livable places.

Methodology for the Cities Ranking

We constructed the city index based on eleven variables. These eleven variables capture a city’s local “greenness,” and some also measure whether a city is a “good citizen.”

Each of the eleven variables is standardized to create mean zero, standard deviation equal to one variable. We assign a weight of .05 to nine of the variables. These include garbage production per capita, the price of gasoline, the price of electricity, the share of public employment in sanitation, recycling laws, the share of land devoted to parks, private vehicles per capita, public transit’s share of total energy consumption, and smoking laws. We assign a weight of .20 to a city’s per-capita income level and we assign a weight of .35 to its particulate matter level. Particulate matter receives a higher index weight due to the immediate morbidity and mortality effects associated with exposure to this pollutant.

This eleven-variable data set is based on three data sources. The Reader’s Digest Survey provides information on city environmental laws, energy prices, garbage production and sanitation employment, and city park space. The transportation data was provided by Jeff Kenworthy and Felix Laube, 2001, The Millennium Cities Database for Sustainable Transport. And the particulate matter data source is the World Bank’s Development Economic Research Group Estimates.

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• Living Green
• Ranking the best (and worst) countries.
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• Living Green: Full Country and City Rankings
• We analyzed data from two top sources covering 141 nations to rank the world's greenest, most livable places. View the complete city and country rankings.
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• Blog: Matthew Kahn PhD -- Environmental and Urban Economics
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• More Environmental Sustainability Index Data
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