Table 1.

Types of COA tools

COA	Definition
PRO measures	Measurement based on a report that comes from the patient (ie, study subject) about the status of his or her health condition without amendment or interpretation of the patient's report by a clinician or anyone else. A PRO measure can be self- or interview administered, provided that the interviewer records only the patient's response. Symptoms or other unobservable concepts known only to the patient (eg, pain severity, nausea) can only be assessed by PRO measures. PRO measures can also assess the patient perspective on functioning or activities that may also be observable by others.
PerfO measures	Based on a task performed by a patient according to standardized instructions and administered by a health care professional. These include measures of gait speed (eg, timed 25-foot walk test), memory recall, and other cognitive testing (eg, digit symbol substitution test).
ClinRO measures	Measurement based on a report that comes from a trained health care professional after observation of a patient's health condition. A ClinRO involves a clinical judgment or interpretation of the observable signs, behaviors, or other physical manifestations thought to be related to a disease or condition.
ObsRO measures	Measurement based on an observation by someone other than the patient or a health professional. This may be a parent, spouse, or other nonclinical caregiver who is in a position to regularly observe and report on a specific aspect of the patient's health. An ObsRO measure does not include medical judgment or interpretation. Examples of ObsROs include a parent report of a child's vomiting episodes or a report of wincing thought to be the result of pain in people who are unable to report for themselves.