Evidence-based design (EBD) 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.
 Evidence-based design (EBD) was popularized by the seminal study by Ulrich (1984) 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 (CHD), 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. The evidence-based design movement began much later 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 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. Architectural researchers have conducted post-occupancy evaluations (POE) 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.
 There is a growing awareness among healthcare professionals and medical planners for the need to create patient-centered environments that can help patients and family cope with the stress that accompanies illness. There is also growing supporting research and evidence through various studies that have shown both the influence of well-designed environments on positive patient health outcomes, and poor design on negative effects including longer hospital stays.
 Using biophilic design concepts in interior environments is increasingly argued to have positive impacts on health and well-being through improving direct and indirect experiences of nature. Numerous studies have demonstrated improved patient health outcomes through environmental measures; exposing patients to nature has been shown to produce substantial alleviation of pain, and limited research also suggests that patients experience less pain when exposed to higher levels of daylight in their hospital rooms. Patients have an increased need for sleep during illness, but suffer from poor sleep when hospitalised. Approaches such as single-bed rooms and reduced noise have been shown to improve patient sleep. Natural daylight in patient rooms help to maintain circadian rhythms and improve sleep.
 According to Heerwagen, an environmental psychologist, medical models of health integrate behavioral, social, psychological, and mental processes. Contact with nature and daylight has been found to enhance emotional functioning; drawing on research from studies (EBD) on well-being outcomes and building features. Positive feelings such as calmness increase, while anxiety, anger, or other negative emotions diminish with views of nature. In contrast there is also convincing evidence that stress could be worsened and ineffective in fostering restoration in built environments that lack nature. 
 Few studies have shown the restorative effects of gardens for stressed patients, families and staff. Behavioural observation and interview methods in post occupancy studies of hospital gardens have shown a faster recovery from stress by nearly all garden users. Limited evidence suggest increased benefits when these gardens contain foliage, flowers, water, pleasant nature sounds, such as birds and water.
 EBD is closely related to performance-based building design (PBBD) practices. As an approach to design, PBBD tries to create clear statistical relationships between design decisions and satisfaction levels demonstrated by the building systems. Like EBD, PBBD uses research evidence to predict performance related to design decisions.
 The decision-making process is non-linear, since the building environment is a complex system. Choices cannot be based on cause-and-effect predictions; instead, they depend on variable components and mutual relationships. Technical systems, such as heating, ventilation and air-conditioning, have interrelated design choices and related performance requirements (such as energy use, comfort and use cycles) are variable components.
 Evidence-based medicine (EBM) is a systematic process of evaluating scientific research which is used as the basis for clinical treatment choices. Sackett, Rosenberg, Gray, Haynes and Richardson argue that "evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients". It is used in the healthcare industry to convince decision-makers to invest the time and money to build better buildings, realizing strategic business advantages as a result. As medicine has become increasingly evidence-based, healthcare design uses EBD to link hospitals' physical environments with healthcare outcomes.
 Research-informed design (RID) is a less-developed concept that is commonly misunderstood and used synonymously with EBD, although they are different. It can be defined as the process of applying credible research in integration with the project team to inform the environmental design to achieve the project goals. Credible research here, includes qualitative, quantitative, and mixed methods approaches with the highest standards of rigor suitable for their methodology.
It is important to understand that the literature for "research-informed" practices comes from education and not from the healthcare disciplines. The process involves application of the outcomes from literature review and empirical investigation to inform design during the design phase, given the constraints; and to share the process and the lessons learnt just like in EDB.
 As EBD is supported by research, many healthcare organizations are adopting its principles with the guidance of evidence-based designers. The Center for Health Design developed the Pebble Project, a joint research effort by CHD and selected healthcare providers on the effect of building environments on patients and staff. Health Environment Research & Design journal and the Health Care Advisory Board are additional sources of information and database on EBD.
 The Evidence Based Design Accreditation and Certification (EDAC) program was introduced in 2009 by The Center for Health Design to provide internationally recognized certification and promote the use of EBD in healthcare building projects, making EBD an accepted and credible approach to improving healthcare outcomes. EDAC identifies those experienced in EBD and teaches about the research process: identifying, hypothesizing, implementing, gathering and reporting data associated with a healthcare project.
 There are four components to evidence-based design:
 In his book Evidence-based Policy: A Realistic Perspective, Ray Pawson suggests a meta-analysis template which may be applied to EBD. With this protocol, the field will be able to provide designers with a source for evidence-based design.
 A systematic review process should follow five steps:
 According to Hamilton, architects have a responsibility in translation of research in the field, and its application in informing designs. He further illustrates a conceptual model architects could use, that identifies four levels of addressing research and methods base on varying levels of commitment: 
 A white paper (series 3/5) from the Center for Health Design presents a working model to help designers implement EBD decision-making. The primary goal is providing a healing environment; positive outcomes depend on three investments:
 All three investments depend on existing research.
 A white paper from the Center for Health Design identifies ten strategies to aid EBD decision-making:
 Evidence-based design has been applied to efficacy measurements of a building's design, and is usually done at the post-construction stage as a part of a post-occupancy evaluation (POE). The POE assesses strengths and weaknesses of design decisions in relation to human behaviour in a built environment. Issues include acoustics, odor control, vibration, lighting and user-friendliness, and are binary-choice (acceptable or unacceptable). Other research techniques, such as observation, photography, checklists, interviews, surveys and focus groups, supplement traditional design-research methods.
Assessment tools have been developed by The Center for Health Design and the Picker Institute to help healthcare managers and designers gather information on consumer needs, assess their satisfaction and measure quality improvements: