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Compound Evidence InstituteEvidence synthesis · established 2023Graded assessments of compounds, trials, methods and supply
Document set current to 30 July 2026
Glossary category

Outcomes and endpoints

Terms describing what a study measures and what the measurement supports.

Terms

17 documents

Table 1. Terms in the outcomes and endpoints category.

TermDefinition
Adverse eventAEAny untoward occurrence in a participant, whether or not attributed to treatment. Ascertained by spontaneous report in most trials, which underestimates incidence relative to systematic questioning.
Anchor outcomeThe outcome the Institute designates as primary for an indication across its whole document set, so that estimates for different compounds in that indication are reported on a common measure.
Clinical outcomePatient-important outcomeAn outcome a person would notice or care about directly: death, an event, a symptom, a function. Distinguished throughout the document set from a surrogate.
Composite endpointAn endpoint counting the first occurrence of any of several component events. Interpretable only when the components are of comparable importance and move in the same direction, and the Institute reports components separately.
Discontinuation for adverse eventsCessation of randomised treatment because of an adverse event. Reported by the Institute in the summary-of-findings table alongside efficacy outcomes rather than in a tolerability annex.
EffectivenessThe effect of an intervention under ordinary conditions of use. Generally smaller than efficacy, principally because adherence and persistence outside a trial are lower.
EfficacyThe effect of an intervention under the conditions of a controlled trial, in a selected population with protocol-driven adherence and follow-up.
Exploratory endpointAn outcome analysed without multiplicity control and without pre-specified inferential status. Hypothesis-generating in every case, including where the result is striking.
MACEMajor adverse cardiovascular eventsMajor adverse cardiovascular events. Conventionally a three-point composite of cardiovascular death, non-fatal myocardial infarction and non-fatal stroke; four- and five-point definitions exist and are not interchangeable.
Number needed to harmNNHThe reciprocal of the absolute risk increase for a harm. Reported alongside the number needed to treat wherever both are estimable.
Patient-reported outcomePROAn outcome reported directly by the participant without interpretation by a clinician. At elevated risk of bias where the intervention produces a perceptible effect that unblinds the participant.
Placebo-subtractedAn effect expressed as the difference between the change in the active arm and the change in the placebo arm. The only form in which the Institute reports a within-arm change.
Primary endpointPrimary outcomeThe outcome on which a trial is powered and against which its success is judged. A trial has one primary endpoint, or a small number designated co-primary with an explicit multiplicity plan.
Responder analysisCategorical responder thresholdAn analysis reporting the proportion of participants reaching a defined threshold. Reported by the Institute alongside the mean because a mean conceals the distribution of response.
Secondary endpointAn outcome measured alongside the primary endpoint. Confirmatory only where it occupies a place in a pre-specified testing hierarchy that was reached.
Serious adverse eventSAEAn adverse event that results in death, is life-threatening, requires hospitalisation, produces persistent disability or is a congenital anomaly. A regulatory classification and not a judgement of severity.
Surrogate outcomeSurrogate endpointA measurement substituted for a clinical outcome on the assumption that a change in one predicts a change in the other. Validation of that assumption requires trial-level evidence across interventions and is available for few surrogates.
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