# Blinded trial

Source: https://onco.cc/terms/blinding/  
OnCo record `blinding` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Keeping patients (single-blind) or patients and doctors (double-blind) from knowing who is on which treatment, so that hopes and expectations cannot colour the results.

## Summary

Blinding protects outcomes that involve judgement: how a patient rates their symptoms, whether a doctor decides a scan shows progression, or when to stop treatment; hard outcomes such as death are less vulnerable. Many cancer trials are open-label because the treatments are too different to disguise (an infusion versus a tablet, distinctive side effects), and they compensate by having scans read by a blinded independent central review (BICR) and by using overall survival, which cannot be biased by knowing the assignment. Unblinding a trial early, for example at an interim analysis, is a formal step overseen by an independent data monitoring committee.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: blinded; double-blind; double-blinded; double blind; single-blind; open-label; open label; unblinded; unblinding; blinded review; blinded independent review

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Blinded_experiment
- Wikipedia: https://en.wikipedia.org/wiki/Blinded_experiment

## Connected records

- terms: [Blinded independent central review (BICR)](https://onco.cc/terms/bicr/), [Blinding (double-blind, open-label, placebo-controlled)](https://onco.cc/terms/double-blind/), [Clinical equipoise](https://onco.cc/terms/clinical-equipoise/), [Clinical trial](https://onco.cc/terms/clinical-trial/), [Endpoint](https://onco.cc/terms/endpoint/), [Placebo](https://onco.cc/terms/placebo/), [Randomised trial](https://onco.cc/terms/randomised-trial/), [Stratified randomisation, allocation concealment and minimisation](https://onco.cc/terms/stratified-randomisation/)

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