Textbook of Usability

Also known as: EBD

Evidence-based design (EBD) is the application of research evidence to architectural and interior design decisions, especially in healthcare settings. It is the architectural parallel to evidence-based medicine: design choices are informed by the best available research about the relationship between the physical environment and human outcomes.

Key findings in evidence-based hospital design:

• Single-patient rooms reduce hospital-acquired infections, improve sleep, reduce noise, and increase patient satisfaction compared to multi-bed wards
• Natural light and views of nature reduce pain, shorten recovery, and improve staff satisfaction (Ulrich, 1984, and subsequent replications)
• Decentralised nursing stations reduce nurse walking by 20–40% and increase direct patient care time
• Sound-absorbing materials reduce hospital noise levels, which routinely exceed WHO recommendations
• Wayfinding design (Lynch's elements) reduces visitor disorientation and clinical staff interruptions

EBD uses research methodologies familiar from other empirical disciplines: controlled studies where possible, quasi-experimental designs comparing wings or facilities, post-occupancy evaluation to measure outcomes, and systematic reviews synthesising evidence across studies.

The approach faces real-world tensions with cost constraints, construction timelines, and operational conventions. Single-patient rooms cost more to build and staff. Decentralised nursing requires more equipment. Evidence-based design advocates argue that lifetime outcomes (fewer infections, shorter stays, better recovery) justify the capital costs — though this calculation depends on institutional priorities and payment structures.

EBD exemplifies the broader argument of this textbook: that design decisions in any domain benefit from empirical evidence about their effects on the humans who use them.