1.1 Definition, History & Core Principles of Evidence-Based Design

Evidence-Based Design Accreditation EDAC

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1 Chapter 1: Foundations of Evidence-Based Design

1.1 Definition, History & Core Principles of Evidence-Based Design 1.2 Comparing Evidence-Based Design (EBD) and Evidence-Based Medicine (EBM) 1.3 The Eight-Step EBD Process Framework 1.4 Who Benefits from EBD & Which Outcomes It Can Influence

2 Chapter 2: Healthcare Context, Systems Thinking & Leadership

2.1 Macro Healthcare Trends, Demographics & Economic Drivers 2.2 The Healthcare Delivery System: Care Settings, Hospital Types & Networks 2.3 The Systems-Based Approach (Formerly the Environment of Care) 2.4 Organizational Culture, Culture Change & Cross-Cultural Design 2.5 Healthcare Stakeholders, Facility Users & Governance Roles 2.6 Executive Leadership, Project Lifecycle Changes & Succession Planning

3 Chapter 3: Healing Environments, Theory & the EDAC Credential

3.1 Healing Environments, Psycho-Neuro-Immunology & Stress Reduction 3.2 Positive Distractions, Biophilia & Roger Ulrich Landmark Research 3.3 Integrative Medicine & Designing Healing and Therapeutic Environments 3.4 Healthcare Workplace Design, Staff Retention & Fatigue Reduction 3.5 Professional Responsibility, Healthcare Outcomes & the EDAC Credential

4 Chapter 4: Research Fundamentals & Evidence Sources

4.1 The Role of Research in Healthcare Architecture & Design 4.2 Types of Evidence: Internal vs. External Evidence 4.3 Literature Searches, Academic Databases & Search Strategies 4.4 Screening, Extracting & Synthesizing Healthcare Design Literature

5 Chapter 5: Evidence Hierarchies & Critical Appraisal

5.1 The Hierarchy of Evidence: Systematic Reviews to Expert Opinion 5.2 Internal Validity, External Validity & Reliability in EBD 5.3 Research Bias, Confounding Factors & Threat Mitigation 5.4 Step 3: The Critical Interpretation & Appraisal Process

6 Chapter 6: Research Methodologies, Data Analysis & the Research Plan

6.1 Quantitative Research Designs, Metrics & Statistical Significance 6.2 Qualitative Methods, Behavioral Observation & Spatial Mapping 6.3 Mixed Methods, Data Triangulation & Research-to-Design Translation 6.4 The Research Process: Research Questions, Research Plans, Ethics & Reporting

7 Chapter 7: Project Setup & Predesign

7.1 Project Setup: Early Capital Planning, Context & Culture, and the EBD Budget 7.2 Step 1: Defining Evidence-Based Vision, Goals & Objectives 7.3 Participative Design, Charrettes & Advisory Councils 7.4 Functional Programming, Adjacencies & Flow Analysis

8 Chapter 8: Hypotheses, Baselines & the Business Case

8.1 Step 5: Formulating Rigorous, Testable EBD Hypotheses 8.2 Step 6: Planning & Collecting Baseline Performance Measures 8.3 The Business Case for EBD: Capital Costs vs. Operational Life-Cycle 8.4 Prioritizing Design Interventions Under Budget Constraints

9 Chapter 9: Designing for Safety: Risk Assessment, Infection, Falls & Medication Safety

9.1 Attributes of a Safe Environment & the Safety Risk Assessment 9.2 Infection Control, Single-Bed Rooms & Hand-Hygiene Design 9.3 Fall Prevention, Same-Handed Rooms & Bathroom Adjacencies 9.4 Medication Safety, Decentralized Nursing Stations & Workflow

10 Chapter 10: Design Phase: Environmental Factors, Concepts & Mock-Ups

10.1 Healthcare Acoustics, Noise Reduction & Sound Absorption 10.2 Circadian Lighting, Natural Daylight & Visual Performance 10.3 Step 4: Creating and Innovating Evidence-Based Design Concepts 10.4 Step 4 Prototyping: Mock-Ups, Simulation & Iterative Evaluation

11 Chapter 11: Construction, Commissioning & Activation

11.1 Step 7: Monitoring Implementation Fidelity & Guarding EBD Intent 11.2 Commissioning: Verifying the Building Meets EBD Intent Before Occupancy 11.3 Activation Readiness, Transition Planning & Finalizing the POE Research Plan

12 Chapter 12: Post-Occupancy Evaluation & Knowledge Sharing

12.1 Step 8: Post-Occupancy Evaluation Methodology & Timing 12.2 Executing the POE Research Plan, Independent Evaluation & Finalizing the Business Case 12.3 Analyzing POE Data, Isolating Environmental Effects & Mixed Outcomes 12.4 Knowledge Dissemination, Peer Review & Continuous Improvement

1.1 Definition, History & Core Principles of Evidence-Based Design

Key Takeaways Explain This Topic AI

The Center for Health Design (CHD) defines Evidence-Based Design (EBD) as 'the process of basing decisions about the built environment on credible research to achieve the best possible outcomes.'

Commonly cited historical roots run from Florence Nightingale's 19th-century sanitary and ventilation reforms to Roger Ulrich's 1984 Science study linking a window view of trees to shorter post-surgical stays.

CHD launched the Pebble Project research collaboration in 2000 and introduced the EDAC credential in 2009 after developing it with more than 100 volunteer industry experts.

CHD study materials describe two things EBD adds to typical design: using available credible evidence to inform decisions and creating new evidence about design outcomes to share with the field.

EBD differs from intuitive design, personal preference, and minimum building codes, which set legal life-safety baselines rather than targets for improved outcomes.

Last updated: September 2026

Definition, History & Core Principles of Evidence-Based Design

Official Definition: The Center for Health Design (CHD) defines Evidence-Based Design (EBD) as "the process of basing decisions about the built environment on credible research to achieve the best possible outcomes."

Evidence-Based Design transforms healthcare architecture from an exercise based primarily on aesthetic preference, intuition, or historical precedent into an accountable, empirical discipline. Rather than viewing buildings merely as physical shelters or capital assets, EBD recognizes the built environment as an active therapeutic modality that directly impacts clinical, operational, financial, and experiential outcomes.

Deconstructing the Official EBD Definition

Each part of the official CHD definition carries meaning:

"The process..." — EBD is not a single milestone, a static checklist, or an architectural style. It is a systematic, multidisciplinary methodology integrated across every phase of a capital project—from initial strategic predesign through occupancy and post-occupancy research.

"...of basing decisions about the built environment..." — Architectural massing, department adjacencies, floor-plate geometry, interior finishes, lighting spectra, acoustics, mechanical ventilation, and technology placement must all be informed by deliberate inquiry rather than subjective assumptions.

"...on credible research..." — Decisions draw upon peer-reviewed empirical literature, rigorous internal institutional metrics, and validated scientific methodologies, critically appraised for validity and generalizability.

"...to achieve the best possible outcomes." — Design interventions are explicitly linked to measurable targets across clinical safety (e.g., healthcare-associated infections, patient falls, medical errors), staff performance (e.g., fatigue, retention, travel distances), and organizational viability (e.g., length of stay, operational ROI).

Connection to Healthcare's Quadruple Aim

EBD serves as an essential physical infrastructure supporting healthcare's Quadruple Aim :

Improving Patient Experience: Enhancing privacy, dignity, acoustic comfort, wayfinding ease, and perceived quality of care.

Improving Population Health: Designing spaces that prevent cross-contamination, promote physical activity, and support preventive community wellness.

Reducing Healthcare Costs: Decreasing length of stay (LOS), mitigating expensive hospital-acquired conditions (HACs), and streamlining clinical workflows.

Improving Staff Well-Being: Providing ergonomic charting spaces, quiet respite rooms, natural daylighting, and reduced physical walking distances to combat clinician burnout and turnover.

Historical Evolution of Healthcare Architecture

Healthcare design has evolved through several distinct paradigms, transitioning from spiritual shelter to mechanical efficiency, and ultimately to empirical, evidence-based science.

Era Predominant Model Key Environmental Principles Primary Drivers

Ancient & Medieval Temple / Monastic Infirmary Spiritual salvation, basic shelter, communal wards Religious charity, isolation of pestilence

19th Century Nightingale Pavilion Hospital Cross-ventilation, daylight, sanitation, 30-bed open wards Crimean War reforms, miasma theory, Florence Nightingale's Notes on Hospitals (1859)

Early 20th Century Sanatorium Movement Sunlight (heliotherapy), fresh air terraces, quietude, hygienic surfaces Tuberculosis containment, Alvar Aalto's Paimio Sanatorium (completed 1933)

Mid-20th Century Industrialized / Hill-Burton Era Deep floor plates, centralized HVAC, artificial lighting, sterile efficiency Hill-Burton Act (1946), biomedical technology, biomedical machinery priority

Late 20th Century Planetree & Consumer Movement De-institutionalization, warm finishes, patient-centered amenities Patient empowerment, Angelica Thieriot (1978), hospitality influence

Modern Era (1984–Present) Evidence-Based Design (EBD) Empirical research, measurable outcomes, standardized processes, POEs Roger Ulrich (1984), The Center for Health Design (founded 1993), Pebble Project (2000), EDAC (2009)

The 19th-Century Foundation: Florence Nightingale

Modern environmental healthcare design originated with Florence Nightingale during the Crimean War (1854). At the British Army Barrack Hospital in Scutari, unsanitary conditions—defective sewers, poor ventilation, overcrowding, and unwashed linens—contributed to very high death rates.

Widely repeated accounts report that hospital mortality fell from roughly 42% to about 2% within months. Historians credit much of that drop to the British Sanitary Commission's 1855 work on drains, sewers, and ventilation, alongside Nightingale's nursing and hygiene reforms—which is exactly why the episode is cited as an early demonstration that the physical environment affects survival.

In her seminal 1859 treatise, Notes on Hospitals , Nightingale established the Pavilion Hospital design:

Long, narrow ward pavilions with windows on opposing exterior walls to create natural cross-ventilation.

Generous ceiling heights and air volume per bed to dilute what the era called 'foul air' (miasma theory).

Wards of limited size (on the order of 30 beds) with beds spaced along the window walls to support ventilation and observation.

Separate pavilions connected only by covered exterior corridors to isolate communicable diseases.

The Sanatorium Movement (Early 1900s)

Before the discovery of streptomycin in 1943, tuberculosis treatment relied entirely on environmental therapeutics. The sanatorium movement placed patients in direct contact with natural elements:

South-facing sun balconies and sleeping porches providing heliotherapy (sunlight exposure).

Extensive cross-ventilation and mountain air exposure.

Alvar and Aino Aalto's Paimio Sanatorium (Finland, completed 1933) stands as a landmark architectural achievement: Aalto specifically designed non-splash washbasins to prevent droplet spread, placed radiant ceiling panels to warm patients' feet without drying the air, utilized noise-dampening materials, and angled windows toward pine forests to reduce patient anxiety.

The Hill-Burton Era and Medicalization (1946–1970s)

Following World War II, the U.S. Congress enacted the Hospital Survey and Construction Act of 1946 (Hill-Burton Act) , distributing federal grants and loans to construct modern community hospitals across the nation.

While this era democratized access to acute care, it introduced significant environmental drawbacks:

Deep floor-plate geometry: Facilities expanded outward into massive rectangular footprints, creating long, windowless interior corridors and staff work areas.

Mechanical dependency: Reliance on centralized HVAC systems eliminated operable windows and natural ventilation.

Artificial sensory deprivation: Fluorescent lighting, hard acoustic surfaces, and monotonous cinderblock construction created sterile, noisy, disorienting environments.

Machine-centric focus: Space planning prioritized the technical adjacencies of diagnostic equipment (X-rays, surgical suites) over human psychological and physiological needs.

The Empirical Turning Point: Roger Ulrich's Landmark Study (1984)

In 1984, behavioral scientist Dr. Roger Ulrich published a pioneering study in Science entitled "View Through a Window May Influence Recovery from Surgery." It is widely cited as a catalyst for modern Evidence-Based Design.

Study Methodology

Design: Retrospective matched-pair analysis of patient records from 1972 to 1981 at a suburban Pennsylvania hospital.

Sample: 46 adult patients recovering from cholecystectomy (gallbladder surgery), paired into 23 matched pairs on factors such as sex, age, smoking status, obesity, prior hospitalization, and floor level.

Intervention: One patient in each pair had a room overlooking a small natural grove of deciduous trees; the matched patient had an identical room overlooking a brown brick building wall.

Quantitative Findings

Shorter Hospital Stays: Patients with tree views had significantly shorter post-operative lengths of stay ( 7.96 days vs. 8.70 days ).

Fewer Potent Analgesics: On postoperative days 2–5, wall-view patients received more doses of moderate and strong narcotic analgesics, whereas tree-view patients relied more on weak analgesics such as aspirin and acetaminophen.

Fewer Negative Nursing Notes: Nurses recorded significantly fewer negative evaluative comments (e.g., "patient is upset," "crying," "needs constant reassurance") for patients facing the natural landscape (averaging 1.13 vs. 3.96 negative notes per patient).

Fewer Minor Complications: Tree-view patients suffered fewer minor post-surgical complications such as persistent nausea or headaches.

Ulrich's study gave healthcare executives and architects early empirical evidence that an environmental feature could be associated with measurable recovery outcomes—not just with preference or comfort.

Institutionalization: The Pebble Project & EDAC

Following Ulrich's research, the field moved rapidly from individual academic studies to an organized industry-wide movement. 1984: Ulrich publishes landmark Science study

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1993: The Center for Health Design (CHD) founded
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2000: Pebble Project research collaboration launched
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2004: Ulrich, Zimring and colleagues publish a major CHD review of the research literature
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2005–2009: CHD develops EDAC with 100+ volunteer industry experts
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2007: Health Environments Research & Design Journal (HERD) launched
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2009: EDAC credential introduced
The Center for Health Design (CHD)

Founded in 1993, The Center for Health Design is a nonprofit organization whose stated mission is to transform healthcare environments for a healthier, safer world through design research, education, and advocacy.

The Pebble Project (Launched 2000)

In 2000, CHD created The Pebble Project , a collaborative research initiative uniting progressive healthcare providers, architectural firms, and manufacturers.

The Premise: Like a pebble dropped into water, each evidence-based healthcare design project creates a ripple effect, generating empirical data that expands the global knowledge base.

Commitment: Participating healthcare systems commit to implementing EBD design interventions, conducting pre- and post-occupancy evaluations, and publicly publishing their clinical, operational, and financial findings.

Early Pebble Partners: Organizations such as Bronson Methodist Hospital (Kalamazoo, MI) and Methodist Hospital/Clarian Health Partners (Indianapolis, IN). Their results were widely publicized: Bronson reported an 11% decline in its overall hospital-acquired infection rate after moving into a facility with private rooms, and Methodist's acuity-adaptable cardiac unit reported roughly 90% fewer patient transfers and 70% fewer medication errors (Hendrich, Fay & Sorrells, 2004). Treat such single-site before-and-after results as promising rather than conclusive—other changes happened at the same time.

EDAC Certification (Launched 2009)

Developed over several years with more than 100 volunteer industry experts, CHD launched the Evidence-Based Design Accreditation and Certification (EDAC) program in 2009. EDAC recognizes individuals—architects, interior designers, healthcare executives, facility managers, clinicians, researchers, students, and others—who demonstrate an understanding of how to apply an evidence-based process to design, including measuring and reporting results.

What Makes a Project Evidence-Based

CHD study materials describe two processes that EBD adds to the typical healthcare design process: using available, relevant evidence to educate the project team and inform design decisions, and creating new evidence that links design interventions to outcomes and is shared with the wider field. In day-to-day project work, those two processes show up as four practical habits:

Base Decisions on Credible Research: Design decisions must be grounded in the best available empirical research from peer-reviewed literature, internal performance data, and validated architectural post-occupancy evaluations.

Set Measurable Goals: Before schematic design begins, the interdisciplinary team must articulate specific, measurable organizational objectives (e.g., "reduce patient falls in telemetry units by 25% within 12 months of occupancy").

Track Outcomes: The project team must systematically collect baseline performance metrics before construction and gather post-occupancy evaluation (POE) data after activation to assess whether design goals were achieved.

Share Results: To advance the field, teams must disseminate their findings—both successes and failures—through peer-reviewed journals (such as HERD ), conferences, and professional repositories.

Distinguishing EBD from Traditional Design Approaches

Be able to differentiate EBD from traditional architectural practice, personal intuition, and regulatory compliance.

Dimension Evidence-Based Design (EBD) Intuitive / Traditional Design Personal Preference Minimum Building Codes

Basis of Decision Credible empirical research & internal clinical data Designer experience, precedent, architectural aesthetic trends Personal tastes of the donor, CEO, or lead designer State statutes, NFPA 101, FGI Guidelines, IBC

Goal Setting Explicit, measurable clinical & operational outcomes Form, aesthetic harmony, spatial efficiency Subjective satisfaction, corporate branding Life safety, structural integrity, minimum clearances

Accountability Testable hypotheses evaluated via pre/post metrics Client sign-off and completion within budget/schedule Stakeholder approval of aesthetic selections Permitting, inspection sign-off, certificate of occupancy

Data Utilization Systematic literature review & critical appraisal Architectural magazines, award-winning portfolios Personal catalogs, vendor marketing materials Code books, prescriptive minimum tables

Post-Occupancy Rigorous POE comparing actual vs. hypothesized outcomes Occasional informal walkthrough; punch-list review None None (unless code violations or life safety complaints arise)

Integrating EBD Into the Traditional Project Phases

CHD's current exam content outline asks candidates to describe the difference between the traditional design approach and how to integrate the EBD process into that approach . EBD does not replace the familiar project phases (predesign, schematic design, design development, construction documents, construction, occupancy); it adds evidence work to each of them:

Project Phase Traditional Approach With the EBD Process Integrated

Planning & predesign Program driven by volume, precedent, and budget Vision, measurable EBD goals, a researcher on the team, and a business case for using EBD

Schematic design & design development Options judged on appearance, fit, and cost Options tested against guiding principles, appraised evidence, hypotheses, and mock-ups

Construction documents & construction Value engineering by line item EBD features tracked, defended with the business case, and verified in the field

Occupancy Punch list and warranty walk-through Baseline-to-POE comparison, lessons learned, and shared results

Caution

EXAM TRAP: Code Compliance vs. Evidence-Based Design

A common scenario-style distractor describes a facility that rigorously complies with the Facility Guidelines Institute (FGI) Guidelines for Design and Construction of Hospitals and municipal building codes, asking if this constitutes an Evidence-Based Design process.

It does not. Building codes and FGI Guidelines establish the legal minimum threshold required for licensure, life safety, and physical accessibility. Merely following prescriptive minimums is mandatory legal practice—not EBD. Evidence-Based Design actively applies targeted research to test hypotheses and optimize outcomes beyond statutory baselines.