• Credit: Michael Gibbs

Evidence-based design (EBD) has largely been associated with health facilities, but the principles of EBD are not domain-specific. They are increasingly recognized as a paradigm for public space, bringing more rigor, accountability, and persuasiveness to design processes.

“When I was in medical training in the early 1970s,” says Dr. Richard Jackson, Hon. AIA, professor at the UCLA School of Public Health and host of the recent PBS series Designing Healthy Communities, “an awful lot that we were taught seemed to have its origin in the craft of medicine and the experiences of experts. Medicine has become much more data-driven.”

And those data sets point to environmental changes at the urban scale, rather than just the scale of the building. “If we think we’re going to turn around these epidemics by simply giving clinical care, we’re fooling ourselves,” Jackson says, noting the higher rates of chronic disease globally. “We have got to start thinking about upstream changes. And that’s where architects come in.”

Caveat Emptor
As changing disease patterns shift the emphasis from external agents to behavior, the process of analyzing a built space’s variables and health effects resembles medicine’s process of diagnosis, hypothesis development, treatment, and monitoring on a communal rather than individual scale. Fields where architects and planners can “diagnose” and “treat” a community include neighborhood design, density, transportation, and availability of features like healthy food, recreational facilities, and green space.

Ray Pentecost, FAIA, director of healthcare architecture at Clark Nexsen and president of the International Academy for Design and Health, cautions that the term EBD is sometimes used loosely as “a cliché for business development” and risks losing credibility.

“Not all research findings can be called evidence,” he says, noting that methodological rigor in EBD requires “generalizability,” internal and external validity, appropriate controlling, attention to the distinction between causation and association, assessment of alternate explanations, public documentation, and replication. “Because best practices change, design should be drawn from a running brook, not a stagnant pond.”

A credible EBD firm builds post-occupancy evaluation and research into its standard procedures, including its contracts and its approach to intellectual property. Methodology complicates the spatial implementation of EBD, however. Funding, politics, and logistics sometimes weigh against analyzing and honoring the evidence. “Longitudinal studies are risky,” says Lawrence Frank, director of the Health & Community Design Lab at the University of British Columbia. “You’re relying on something to happen that hasn’t happened yet. Someone said they’re going to build a train line, there’s a change in administration, and the next elected official doesn’t want to build that—it was the last person’s idea. So there you are with half a million dollars invested and no return.”

Yet some jurisdictions see the value of outcome studies. In 2008, University of Pennsylvania researchers studied body mass index and activity levels before and after Charlotte, N.C., built a light rail system, documenting that transit riders were more active than nonriders and lost weight. Frank and his colleagues in the Strategies for Metropolitan Atlanta’s Regional Transportation and Air Quality (SMARTRAQ) group recently extended their Atlanta investigations to control for attitudes toward walkability and mismatches with subjects’ actual neighborhoods, establishing that built-environment variables still account for differences in walking, car use, and obesity—even when self-selection is factored in.

In another study of activity, SMARTRAQ members distinguished between mixed-use development and areas where retail is close to street frontage. The latter neighborhoods had greater social capital than districts dominated by surface parking. “Just having shops and services in your neighborhood doesn’t mean you’re going to get out and walk around and enjoy your neighbors more,” Frank says. “What does? Having it done in a way that supports a local pedestrian environment.”

“When you’re talking public space, the notion of public good becomes more difficult,” says Mallika Bose, chair of the Environmental Design Research Association. “How many people use it? Do people feel happier when they are there? How you define the problem often provides a boundary for the answer,” she says. Other public space analyses are systematic without being quantitative. Enrique Peñalosa, former mayor of Bogotá, Colombia, has one word for that metric: “Happiness.”

“It’s not scientific,” he says, “but you can measure that very easily by how people behave and by asking them. But you don’t necessarily say ‘happy.’ You talk about the intuitive—comfort, image, access, linkage, activities, uses, and sociability.”

Broader Channels of Investigation
New York City has been an active design epicenter, with municipal agencies collaborating with AIA New York as well as scholars representing institutions such as Georgia Tech, Johns Hopkins University, and the Society for Public Health Education to produce the “Active Design Guidelines” (ADG) and its supplements.

Karen K. Lee, senior adviser at the New York City Department of Health and Mental Hygiene (NYC DOHMH), notes that the ADG series has gone national. Its newest addenda, “Affordable Designs for Affordable Housing,” which highlights cases from San Antonio and Atlanta as well as New York City; and “Active Design: Shaping the Sidewalk Experience”—which draws on contributions from Louisville, Ky., Nashville, Tenn., Birmingham, Ala., Portland, Ore., and Seattle—have made a notable impact on how built environmental design and metrics can remake the city. And AIA New York’s annual Fit City symposium series—now in its eighth year in partnership with NYC DOHMH—has spawned FitNation conferences in New Orleans, Washington, D.C., and New York (also co-organized by NYC DOHMH and AIA New York), with funding from the U.S. Centers for Disease Control and Prevention, and the participation of the U.S. Department of Housing and Urban Development.

Lee acknowledges that the messages conveyed through research and the political and economic processes that have shaped the U.S. built environment can sometimes appear as being at odds. In this instance, however, that perception is flawed. “The assumption that because something is more effective that it might be more expensive. is not necessarily playing out,” Lee says.

For instance, affordable housing case studies often conclude that active-design interventions for various building typologies were low-cost or cost-neutral. And when cities designate certain streets as “play streets” in the summer months, the unexpected benefits anecdotally reported by community organizers often include increased socialization among neighbors.

Jackson argues that investment in healthier spaces would lighten economic burdens, and he is optimistic about what’s achievable if research guides civic design, even if it takes a generation or more to unfold. “I remember telling one of my kids that people once smoked on airplanes,” he says. The reply: “Dad, you’re making that up.” If a future generation comes to view cul-de-sacs without sidewalks and hour-long commutes the way that today’s kids view lighting a cigarette on an airplane, it may be because today’s architects, planners, and developers saw the built environment less as a short-term profit center and more as the object of verifiable public knowledge.