a measurement based on a report of observable signs, events, or behaviors related to a patient’s health condition, provided by someone other than the patient or a health professional. These observers are typically parents, caregivers, or others who see the patient in daily life. ObsROs are especially valuable for patients who cannot reliably self-report, such as infants or individuals with cognitive impairments. Importantly, an ObsRO does not include medical judgment or interpretation — it records only what the observer has directly seen or heard.
Abbreviation: ObsRO
Example
In a pediatric clinical trial for a new anti-nausea drug, a parent completes a daily log recording each time their child vomits. This record serves as an Observer-Reported Outcome (ObsRO) because the child is too young to accurately report their own symptoms.