The evidence-based design wheel

March 1, 2007
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A new approach to understanding the evidence in evidence-based design

Evidence-based design (EBD) is an approach to environmental design (architectural, interior, and landscape) that aspires to base design decisions on documented research and well-established best practices, with the aim of improving outcomes.1,2,3 Evidence-based design is increasingly common in the design of healthcare facilities, where the approach has found support among healthcare administrators, many of who are familiar with the conceptually comparable notion of evidence-based medicine. Healthcare environments designed on the basis of solid research evidence are intended to improve patient safety, reduce stress, increase care delivery effectiveness, and enhance quality of care3—objectives that contribute to the overarching goals of improved patient, staff, and organizational outcomes.1 These are achievable when the environment is designed to be therapeutic for patients, supportive of family, efficient for staff, and restorative for all.1,4,5

Copyright ©2007 Kahler Slater Architects Inc. All rights reserved.

Environmental design research in healthcare settings has increased steadily over the last several decades. The most extensive review of the research literature to date (covering more than 600 studies) was conducted in 2004 by Roger Ulrich, Craig Zimring, and colleagues in a report for The Center for Health Design and supported by the Robert Wood Johnson Foundation.3 This impressive study organizes the substantial research knowledge base on the effects of the environment in terms of various outcomes: staff stress and fatigue, effective care delivery, patient safety, patient stress and other patient outcomes, and overall healthcare quality.

In my work as a director of research and education in an architectural firm, I have conceptualized the collective findings of the studies reviewed by Ulrich et al, as well as other rigorous, high-impact studies identified in our own research endeavors in terms of 12 outcome-linked environmental factors that directly contribute to the healing environment. This conceptualization is illustrated in a colorful and engaging graphic device, the EBD Wheel (figure). Whereas Ulrich et al approach the EBD research literature from an outcomes perspective, the EBD Wheel represents a factors-oriented view, prompted in part by a reading of an earlier article by Ulrich on the effects of healthcare environmental design on medical outcomes, which organizes the literature in terms of “environmental characteristicsé that can affect outcomes”.5

It should be noted that some factors are relatively objective (single patient room, air quality), while others are relatively subjective (access to nature, positive distractions)—yet all are equally important to the healing environment equation. To ensure against interpreting the 12 factors as a mixed medley of elective features, they are conceptually linked in the EBD Wheel within the unifying construct of the healing environment to which the factors contribute. Taken together, the 12 environmental factors and the overall healing environment concept comprise a comprehensive, strategic, values- and evidence-based set of design responses that create therapeutic healthcare environments,4 i.e., curative settings that support healing and improve the healthcare experience.

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