a single, clearly defined aspect of health, disease impact, or well-being that is considered important to measure. Domains represent distinct concepts such as symptoms (e.g., pain), functions (e.g., mobility), biological processes (e.g., biomarkers like C-reactive protein), or broader life impacts (e.g., quality of life).
Synonyms: Outcome Domain, concept, item
Example
In a clinical trial testing a new treatment for rheumatoid arthritis, researchers include several domains to capture the treatment’s impact:
Pain
Physical function
Fatigue
Each of these represents a distinct domain that reflects a specific aspect of the patient’s health and the treatment’s effect.