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.