Methodology
The 2008 US City Rankings were developed using a combination of primary and secondary research directed by SustainLane. The study tracks the same data sources as in previous years and is supplemented by a new water supply metric for 2008. The 50 most-populous US cities were included in the study, based on population as measured by the US Census Bureau.
Data and information from these cities are drawn from surveys and interviews from 2007-2008 and from publicly available sources published in the period between 2002-2008.
Overall Rankings
The overall rankings were determined by averaging 16 individual category rankings, each of which was multiplied by a weighting of 0.5, 1, or 1.5 (see “Weighting of Data” for details). The resulting cumulative totals ranged from 90.13 out of 100 for the highest-scoring city (Portland, Oregon) to 64.85 out of 100 for the lowest-scoring city (Mesa, Arizona).
Criteria for City Selection
The 50 most-populous US cities (based on 2004 US Census data) were selected as the universe for the study. Data was collected on a city-basis except for four categories, due to availability. Regional public transit ridership, roadway congestion, and metro area sprawl (a subcomponent of the planning category) data were collected on a metropolitan area basis. Air quality data was gathered on a county-wide basis.
Criteria for Category Selection
During the development of SustainLane’s first US City Rankings in 2004/5, a number of experts in the field of urban sustainability were consulted on the original matrix of categories to be included. Since that time, SustainLane actively engages practitioners in the field of sustainability and augments and adapts the categories and metrics as recommended. Each year, the Rankings are peer- reviewed for a “reality check” prior to the data collection process. SustainLane also incorporates feedback received from city sustainability managers, and each year the Rankings become a little more challenging, which reflects ongoing accomplishments in urban sustainability.
Criteria for Data Set Inclusion
There are two criteria for how data was selected:
a) Data or information sets that are free of political bias and are of high quality, as measured by their use and acceptance as best measures in respected academic, NGO, and government circles.
b) Ease of standardized collection. Air quality data, for instance, is available in a standardized format, freely available (Median Air Quality Index) from the US EPA.
2008 Data Collection and Research Methods
Primary research consisted of email and phone surveys administered to the 50 subject cities between August 2007 and December 2007. City contacts included environmental or sustainability departments, energy offices, departments of public works and solid waste, water departments, mayors' offices and planning departments. Non-Governmental Organizations (NGOs) working directly with subject cities were also surveyed or interviewed. A total of 45 cities responded to the survey. For the cities that did not respond to the survey, rankings were determined by data from public and non-governmental data sources only.
Data was adjusted on a per capita basis for local food and agriculture (farmers markets and community gardens), as well as for green (LEED) buildings.
In total, over 100 respondents were surveyed by email or telephone, or they were interviewed in person. A list of these people and their city or organizational affiliations is available upon request from SustainLane.
Public Data Sources
Public data from the most current sources were combined in each category to provide ranking metric by issue, listed in italics.
Commute to Work
2005 US Census/American Fact Finder commute-to-work information (released in July 2007): Public transportation ridership percentage, walk-to-work percentage, bike-to-work percentage, carpool-to-work percentage, drive-alone-to-work percentage.
Metro Transportation
Data from Texas Transportation Institute’s 2007 Urban Mobility Study analyzing regional general public transit ridership.
Metro Congestion
Data from Texas Transportation Institute’s 2007 Urban Mobility Study analyzing regional freeway and surface road congestion by metro region.
Air Quality
US EPA air quality data and information for all of 2007 (Median Air Quality Index, combined with US EPA Clean Air Act Non-Attainment information, converted to a numerical scale).
NGO and Public information
NGO and public data sources were combined in each category to provide ranking metric by issue, listed in italics.
Tap Water Quality
Environmental Working Group's December 2005 US city drinking water database, “National Assessment of Tap Water Quality.”
Green (LEED) Building
Number of US Green Building Council's Leadership in Energy and Environmental Design (LEED) certified and registered buildings from US Green Building Council, adjusted per capita. A greater weighting was given to data for LEED Certified (over LEED Registered) and for LEED Platinum or LEED Gold buildings (versus LEED Silver or LEED Certified).
Local Food & Agriculture
Number of community gardens and number of farmers markets per city, with additional credit given to those farmers markets accepting WIC (women, infant, children) and food stamps. This data came from both NGOs and the US Department of Agriculture, as well as from cities themselves. Cities and/or NGOs provided the number of community gardens per city. Farmers markets were weighted by the number of each city's markets accepting food stamps and WIC credits.
Planning/Land Use
Urban sprawl data from Smart Growth America's December 2002 study.
Percent of city land area devoted to parks came from Trust for Public Land (2002 study) and from 2007 SustainLane primary research.
Housing Affordability
We studied median US housing prices and median US incomes, according US Census Bureau data. Cities with living wage ordinances were given extra credit.
Natural Disaster Risk
Data from Risk Management Solutions' 1999 'Catastrophic Risk in the United States' and SustainLane primary research: cumulative measure of hurricane risk, flood risk, tornado super outbreaks, earthquake risk, and devastating hail risk.
Green Economy
Data from USGBC and SustainLane Primary research. Measures clean technology incubator, green business activity, local/farmers markets per capita and LEED buildings per capita data.
Exclusive SustainLane Primary Research Categories
Energy and Climate Change Policy
SustainLane primary research on greenhouse gas reduction tracking, goals and inventories, cities' overall renewable energy use percentage and alternative fuel fleet data.
City Innovation
SustainLane primary research on Environmentally Preferable Purchasing programs, commercial and residential green building incentives, carpooling coordination, car-sharing programs (public or private), and extra credit city innovation (general category).
Knowledge Base/Communications
SustainLane primary research on cities' sustainability plans; management organization of environmental/sustainability functions; research partnerships with federal laboratories and/or non-governmental organizations; measurement of organizational structures that ensure long-lasting sustainability program metrics and success.
Water Supply
Data analyzed includes: distance to primary sources of untreated fresh drinking water, dependence on snow pack and water tables, history and trends of drought or saltwater intrusion, population growth trends and daily water use per capita.
Weighting of Data
Of the 16 data categories, 11 received a weighting of 1. The remaining five categories were weighted as follows:
- Water supply: 1.5
Maintaining a stable water supply is an increasingly crucial issue. Without steady fresh water availability, no city can persist into the future. Cities importing water over long distances often depend on high-energy consuming diesel pump systems, which increases the energy consumption of residents in those cities. Aqueducts crossing multiple major quake faults, as in California, also increase water supply stability risk. - Commute to work: 1.5
Commuting measures of biking, walking, public transit, or carpooling have numerous direct and indirect impacts on other categories, including air quality, water quality from surface run-off, greenhouse gas emissions contributing to global climate change, road congestion and economic efficiency (expenditures for gas leave the local economy). - Congestion: 0.5
These impacts are of a secondary nature, such as less fuel efficiency and less public transportation efficiency. - Housing Affordability: 0.5
These impacts are of a secondary nature, as higher housing prices negatively affect the environment because they force more residents and service workers to commute long distances. - Natural disaster risk: 0.5
Outcomes depend on probabilities as calculated by insurance information based on historical data and are unlikely in any given year snapshot.
John D. says:
I live in Honolulu. I think you are quite aware Honolulu doesn't fit easily in the indexing assumptions of your study at sustainlane.com.
Our middle position 17/50 in your study is being heralded here as "proof" of great sustainability and good island energy and waste disposal management, even though we are heavily dependent on fossil fuel, and our tourism (now down 17.3%) is almost 100% dependent on airline (concentrated) fuel.
You report: "Honolulu could greatly increase its sustainable factor once it develops incentive programs for green building and harnesses more energy from ample sunshine and wind."
But we are building on scarse agricultural land, now. We are the only State (in USA) where judges can lawfully consider impact on aesthetics in their rulings, to protect tourism - our form of sustainability.
Honolulu also has one of the shortest BUT most time-consuming Rush-Hour commutes to work in the Nation (your highest weight of 1.5). Our Rail Transit is on the Ballot.
Also, your measure of "sustainability" does not make a distinction between Cities that recently adopted its first Sustainability Plan, and those that have done more than just "plan". Honolulu just adopted it last year!
Your definition of City area vs. Air Quality area: "Regional public transit ridership, roadway congestion, and metro area sprawl... data were collected on a metropolitan area basis. Air quality data was gathered on a county-wide basis."
So, Air & Water Quality gets the highest score. Yet, groundwater is contaminated by decades of old-fashioned insecticide agriculture. And Surface run-off goes into the ocean, not the fresh water supply, but affecting our fishing. Even our sewers drain into the ocean sometimes. Almost Paradise, on the "surface."
May I please have a list of your sources and interviews for your Honolulu data? I happen to live here, and we need more than just clean air to be "sustainable."
ALOHA
J. DeVilbiss, PhD.
Please@hawaii.rr.com
Duane K. says:
For indicators, a lower ranking is better. In ranking cities, a higher ranking is better. How do yo get from one to the other?
John D. says:
Hello Duane K.
I don't understand your question. "Indicators" ?
They rank Metropolitan areas, not Cities. If a metropolitan area is really spread out, then they rank more sustainable if they can get around using fuel efficiently.
The ranking is very complicated, and has weight factors (applied without justification).
Duane K. says:
The lower the ranking on a study category, the better the score. On the other hand, when you rank cities it is the higher value that counts. How do you reconcile that?
Ken O. says:
John D-
Like everyone else, we are aware that Hawaii is heavily reliant on imports. In fact, we posted a photo of Honolulu's airport--did you see it? See below for inline comments:
"we are heavily dependent on fossil fuel, and our tourism (now down 17.3%) is almost 100% dependent on airline (concentrated) fuel."
-- Every major US city is reliant on fossil fuels. Name one city not heavily dependent on gas or diesel. Hawaii could be served in the future by more energy efficient transport: sailboats and other ships.
"Honolulu also has one of the shortest BUT most time-consuming Rush-Hour commutes to work in the Nation (your highest weight of 1.5). Our Rail Transit is on the Ballot."
-- As someone else has mentioned, building live/work/play spaces closer together (mixed use) is better than shoveling everyone about on trains, but trains are a definite improvement over freeways. In every industrial society which uses less energy than the US, those societies have trains: China, Japan, Korea, Europe, India, etc.
"Also, your measure of "sustainability" does not make a distinction between Cities that recently adopted its first Sustainability Plan, and those that have done more than just "plan". Honolulu just adopted it last year!"
-- Sustainability as you know is a new field. The first major US cities to have sustainability plans were SF and NYC, in 1996/97. Going forward, just as with USGBC's LEED rating system we are increasingly raising the bar to differentiate between different cities' efforts and results.
Ken O. says:
(continued)
"Your definition of City area vs. Air Quality area: "Regional public transit ridership, roadway congestion, and metro area sprawl... data were collected on a metropolitan area basis. Air quality data was gathered on a county-wide basis...So, Air & Water Quality gets the highest score.."
-- Most of our data is measured within city boundaries. Some types of data do not stop at the city border, air quality being amongst them. Air Quality data is taken from US EPA--please ask them if you have problems with their data.
By US EPA standards, Honolulu has the cleanest air compared with any of the other 49 largest US cities in our study.
We did not officially rank Honolulu's Water Quality, as you can see from this page:
http://www.sustainlane.com/us-city-rankings/categories/tap-water-quality
Every city on the planet faces groundwater contamination from gas stations, car exhaust pollution, agricultural, industrial and urban runoff, wastewater treatment and other sources. Do not think of Honolulu as the "winner" for air quality, but rather, that the city is "advantaged." Every city has room for improvement. Thanks again for your comments.
Ken Ott
Director, City Rankings
SustainLane.com
Ken O. says:
Duane and John, please see my responses below--
Duane K. says: "For indicators, a lower ranking is better. In ranking cities, a higher ranking is better. How do yo get from one to the other?"
-- For the indicators as well as the cities, a lower ranking is better. Think less is more.
John D. says: "Hello Duane K. I don't understand your question. "Indicators" ? They rank Metropolitan areas, not Cities. If a metropolitan area is really spread out, then they rank more sustainable if they can get around using fuel efficiently. The ranking is very complicated, and has weight factors (applied without justification)."
-- John, we ranked US Cities, not Metro areas. As part of ranking the cities, we used a few data points from larger sets of data, because city-specific data was not available. These included, as you know, Air Quality, Metro/Regional Public Transit Ridership, and Metro Traffic Congestion.
The ranking is not complicated: we rank cities in each of 16 categories, average their scores, and rank them based on overall performance. Voila.
Weighting of factors was carefully considered, since having an ample fresh water supply is more critical to urban survival than how many hours someone sits in traffic per year. For a city's economic metabolism and for people's quality of life, being able to get around without a car is very important and affects many other categories, which is why we weight City Commuting heavily.
Duane K. says: "The lower the ranking on a study category, the better the score. On the other hand, when you rank cities it is the higher value that counts. How do you reconcile that?"
-- Duane, a lower score is better for a city within a category, as well as in the overall ranking of the 50 cities.
Hope this helps.
Cheers,
Ken
John D. says:
Aloha! Ken O.
Thank you for your ellucidations.
The only problem I see is that (though other cities have a Rail system),in HONOLULU, Rail fuel use per passenger mile is greater than by car. We have many valleys, and Rail cannot serve the valleys.
Rail is less energy efficient HERE because our commutes are short in distance, because judges can make decisions here based on aesthetics (protecting the Vew) deciding the route, and because cars are more and more energy efficient. The Rail will rust in no time in our salty ocean air.
We are an island in the Pacific, and it is customary for many people to simplistically assume that a rail like N.Y. City is better than cars here. In N.Y. Rail is underground. I am a geologist, and if you've ever tried to make a hole on Oahu you would know you hit super hard basalt right away, and have to dynamite to go a few feet. And the last thing we want in Honolulu is N.Y. city lifestyle! : )
About fossil fuel, you happen to use two words: "reliant" and heavily "dependent" - but we are in the middle of the Pacific Ocean, get our produce (not via airplanes) by ocean cargo. We can't walk from county to county. And because our sustainability is based on tourism, we can't set up wind or wave energy generation and flat land is at a premium, the OPEC station in Big Island FAILED (using water temperature contrast from deep water to create, allegedly, energy).
Hawaii is just so exceptional, your study assumes it can achieve sustainability in ways other cities do, yet it cannot. Therefore the weight factors, specially that of the Rail that is not here (doesn't follow the old railcar route, and has to condemn very expensive properties because it cannot go underground), makes Honolulu look like position 17/50.
I think there are errors in the way Honolulu was rated. Tap water was not included?
Hope this helps and is to the point. I greatly admire your response.
ALOHA
J. DeVilbiss,
Jim B. says:
So, I'm still unclear: is the fuel used to import food and other goods taken into account? If so, I wonder how cities stack up to small towns...
Bob S. says:
Hi Ken:
Can you see a city using these metrics internally? That is, as a source for policy direction? Obviously, some of these measures are largely outside the control of city policy-makers, such as state air quality, metro planning and land use outcomes, and to some extent, housing affordability. Aside from that, your metrics are standardized across cities for ranked comparisons, have you devised a methodology-weighting method that takes into account change over time internal to the city's themselves? Thanks.
ob Stokes