Evidence-based design

Evidence-based design is the process of constructing a building or physical environment based on scientific research to achieve the best possible outcomes. Evidence-based design is especially important in evidence-based medicine, where research has shown that environment design can affect patient outcomes. It is also used in architecture, interior design, landscape architecture, facilities management, education, and urban planning. Evidence-based design is part of the larger movement towards evidence-based practices.

Background

Evidence-based design was popularized by the seminal study by Ulrich that showed the impact of a window view on patient recovery. Studies have since examined the relationships between design of the physical environment of hospitals with outcomes in health, the results of which show how the physical environment can lower the incidence of nosocomial infections, medical errors, patient falls, and staff injuries; and reduce stress of facility users, improve safety and productivity, reduce resource waste, and enhance sustainability.
Evidence in EBD may include a wide range of sources of knowledge, from systematic literature reviews to practice guidelines and expert opinions. Evidence-based design was first defined as "the deliberate attempt to base design decisions on the best available research evidence" and that "an evidence-based designer, together with an informed client, makes decisions based on the best available information from research and project evaluations". The Center for Heath Design, a non-profit organization that supports healthcare and design professionals to improve the understanding and application of design that influence the performance of healthcare, patient satisfaction, staff productivity and safety, base their model on the importance of working in partnership with the client and interdisciplinary team to foster understanding of the client, preferences and resources.
The roots of evidence-based design could go back to 1860 when Florence Nightingale identified fresh air as "the very first canon of nursing," and emphasized the importance of quiet, proper lighting, warmth and clean water. Nightingale applied statistics to nursing, notably with "Diagram of the causes of mortality in the army in the East". This statistical study led to advances in sanitation, although the germ theory of disease was not yet fully accepted.
Nightingale was also an enthusiast for the therapeutic benefits of sunlight and views from windows. She wrote: "Second only to fresh air … I should be inclined to rank light in importance for the sick. Direct sunlight, not only daylight, is necessary for speedy recovery … I mention from experience, as quite perceptible in promoting recovery, the being able to see out of a window, instead of looking against a dead wall; the bright colours of flowers; the being able to read in bed by the light of the window close to the bed-head. It is generally said the effect is upon the mind. Perhaps so, but it is not less so upon the body on that account...."
Nightingale’s ideas appear to have been influential on E R Robson, architect to the London School Board, when he wrote: “It is well known that the rays of the sun have a beneficial influence on the air of a room, tending to promote ventilation, and that they are to a young child very much what they are to a flower.”
The evidence-based design movement began in the 1970s with Archie Cochranes's book Effectiveness and Efficiency: Random Reflections on Health Services. to collect, codify, and disseminate "evidence" gathered in randomised controlled trials relative to the built environment. A 1984 study by Roger Ulrich seemed to support Nightingale's ideas from more than a century before: he found that surgical patients with a view of nature suffered fewer complications, used less pain medication and were discharged sooner than those who looked out on a brick wall; and laid the foundation for what has now become a discipline known as evidence-based design. Studies exist about the psychological effects of lighting, carpeting and noise on critical-care patients, and evidence links physical environment with improvement of patients and staff safety, wellness and satisfaction. Architectural researchers have studied the impact of hospital layout on staff effectiveness, and social scientists studied guidance and wayfinding. In the 1960s and 1970s numerous studies were carried out using methods drawn from behavioural psychology to examine both people’s behaviour in relation to buildings and their responses to different designs – see for example the book by David Canter and Terence Lee More recently, architectural researchers have conducted post-occupancy evaluations to provide advice on improving building design and quality. While the EBD process is particularly suited to healthcare, it may be also used in other fields for positive health outcomes and provision of healing environments.
While healthcare proved to be one of the most prominent sectors to examine the evidence base for how good design benefits building occupants, visitors and the public, other sectors also have considerable bodies of evidence. And, many sectors benefit from literature reviews that draw together and summarise the evidence. In the UK some were led by the UK Commission for Architecture and the Built Environment, a government watchdog established by the Labour Party following its election in 1997 and commitment to improving the quality of the UK stock of public sector buildings. Other reviews were supported by various public or private organisations, and some were undertaken in academia. Reviews were undertaken at the urban scale, some were cross-sectoral and others were sector based gives an overview of the field as it was in 2006.

A cautionary note about the strength of evidence in the built environment

In supporting evidence-based design, some caution is needed to ascertain the robustness of the evidence: the architectural psychology movement eventually drew criticism for its tendency towards ‘architectural determinism’ – a confusion between correlation and causality with the implication that there were mechanistic and causal links between the built environment and human behaviour. As some of the studies reviewed below reveal, the evidence is often weak or, worse, conflicting. In an early review of evidence in the healthcare sector, Rubin, Owens & Golden examined the medical literature for research papers on the effect of the physical environment on patient outcomes. They concluded that, if the demanding standards of proof used in medical research were used, almost all the studies would have to be regarded as methodologically flawed or at least limited. Unfortunately strongly held opinions are not the same as rigorously collected evidence.

Evidence-base for architecture generally, housing and urban environments

In 2002, CABE published a cross-sectoral study that set a pattern by reviewing a selection of the evidence for healthcare buildings, educational buildings, housing, urban environments, and business premises. It claimed: “Good design is not just about the aesthetic improvement of our environment, it is as much about improved quality of life, equality of opportunity and economic growth. … Good design does not cost more when measured across the lifetime of the building or place …”
At the urban scale, in 2001, CABE and DETR published a study on the value of urban design which includes a literature review plus some case studies.
In New Zealand, a landmark review
was supported by the Ministry for the Environment. The study categorised the evidence as conclusive, strong, suggestive or anecdotal, and also noted the difficulty of establishing causation since various design elements may be found in combination with other features. The authors state that urban design is context-specific and cautions against automatically adopting what works elsewhere in New Zealand.
In its 2003 review of the evidence about housing CABE expressed similar concerns about the evidence base when it said: “The most striking finding in a review of the literature relating to the quality of residential design is the almost complete absence of any empirical attempts to measure the implications of high quality on costs, prices or values.”
David Halpern’s book brings together and reviews a substantial number of studies covering among other issues: mental ill-health in city centres; social isolation in out of town housing estates; residential satisfaction; and estate layouts, semi-private spaces and a sense of community. He concludes that there is substantial evidence to show the physical environment has real and significant effects on group and friendship formation, and on patterns of neighbourly behaviour.
Other literature reviews include a 2006 study by the Scottish Executive and one by the UK NWDA/RENEW North West.

Public open space

CABE’s 2004 literature review on public open space draws attention to the physical and mental health benefits associated with access to recreational space, as well as the environmental value of biodiversity and improved air quality. In a follow up 2005 study entitled Does Money Grown on Trees? CABE assessed the impact on the value of residential property of proximity to a park, drawing on valuations prepared by local property experts in which external variables were controlled for. Economic and non-monetary benefits from the proximity were identified.

Schools and Higher Education

A comprehensive review of the literature was undertaken in 2005 for the Design Council. It concluded that there was evidence for the effect of basic physical variables on learning but that once minimum standards were achieved, further improvements were less significant. The reviewers found forceful opinions on the effects of lighting and colour but that the supporting evidence was conflicting. It was difficult to draw generalizable conclusions about other physical characteristics, and the interactions between different elements was as important as single elements.
Other literature reviews of the education sector include two by Price Waterhouse Coopers and one by researchers at the University of Salford.
In the higher education sector, a review by CABE reports on the links between building design and the recruitment, retention and performance of staff and students. Fifty articles are reviewed, and five new case studies reported.