Clinical Trial Unblinding Event

A Clinical Trial Unblinding Event is a Clinical Trial Event that occurs when all information about treatment or intervention becomes available to the trial's party from whom it has been hidden, whether by accident or on purpose.

• AKA: Unblinding.
• Context:
  • It can range from being a Post-Clinical-Trial Unblinding to being a Premature Clinical Trail Unblinding.
• Example(s):
  • …
• Counter-Example(s):
  • Blind Clinical Trial Review,
  • Clinical Trial Blinding,
  • Placebo Effect.
• See: Blinded Experiment, Open-Label Trial, Clinical Trial Protocol, Placebo, Treatment Group, Control Group Good Clinical Practice, Confirmation Bias, Medical Bias.

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References

2021

• (Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Blinded_experiment#Unblinding Retrieved:2021-11-21.
  • Unblinding occurs in a blinded experiment when information becomes available to one from whom it has been masked. In clinical studies, unblinding may occur unintentionally when a patient deduces their treatment group. Unblinding that occurs before the conclusion of an experiment is a source of bias. Some degree of premature unblinding is common in blinded experiments. When a blind is imperfect, its success is judged on a spectrum with no blind (or complete failure of blinding) on one end, perfect blinding on the other, and poor or good blinding between. Thus, the common view of studies as blinded or unblinded is an example of a false dichotomy. Success of blinding is assessed by questioning study participants about information that has been masked to them (e.g. did you receive the drug or placebo?). In a perfectly blinded experiment, the responses should be consistent with no knowledge of the masked information. However, if unblinding has occurred, the responses will indicate the degree of unblinding. Since unblinding cannot be measured directly, but must be inferred from participants' responses, its measured value will depend on the nature of the questions asked. As a result, it is not possible to measure unblinding in a way that is completely objective. Nonetheless, it is still possible to make informed judgments about the quality of a blind. Poorly blinded studies rank above unblinded studies and below well-blinded studies in the hierarchy of evidence.

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