Blinded Clinical Trial

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A Blinded Clinical Trial is a clinical trial that is a blinded experiment (which withholds any information which may influence the participants until after the trial is completed).



References

2021a

  • (Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Blinded_experiment Retrieved:2021-11-21.
    • In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expectations, observer's effect on the participants, observer bias, confirmation bias, and other sources. A blind can be imposed on any participant of an experiment, including subjects, researchers, technicians, data analysts, and evaluators. In some cases, while blinding would be useful, it is impossible or unethical. For example, it is not possible to blind a patient to their treatment in a physical therapy intervention. A good clinical protocol ensures that blinding is as effective as possible within ethical and practical constraints.

      During the course of an experiment, a participant becomes unblinded if they deduce or otherwise obtain information that has been masked to them. For example, a patient who experiences a side effect may correctly guess their treatment, becoming unblinded. Unblinding is common in blinded experiments, particularly in pharmacological trials. In particular, trials on pain medication and antidepressants are poorly blinded. Unblinding that occurs before the conclusion of a study is a source of experimental error, as the bias that was eliminated by blinding is re-introduced. The CONSORT reporting guidelines recommend that all studies assess and report unblinding. In practice, very few studies do so.[1]

      Blinding is an important tool of the scientific method, and is used in many fields of research. In some fields, such as medicine, it is considered essential. In clinical research, a trial that is not a blinded trial is called an open trial.

  1. Bello, Segun; Moustgaard, Helene; Hróbjartsson, Asbjørn (October 2014). “The risk of unblinding was infrequently and incompletely reported in 300 randomized clinical trial publications". Journal of Clinical Epidemiology. 67 (10): 1059–1069. doi:10.1016/j.jclinepi.2014.05.007. ISSN 1878-5921. PMID 24973822

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2008

  • (Upton & Cook, 2008) ⇒ Graham Upton, and Ian Cook. (2008). “A Dictionary of Statistics, 2nd edition revised." Oxford University Press. ISBN:0199541450
    • QUOTE: ... Blinding: A method of avoiding bias in the context of treating a disease. In a medical experiment, the comparison of treatments could be biased if either the patient, the doctor administering the treatment, or the data analyst knew which treatment was allocated to which patient. If the patient (or the doctor, or the data analyst) is unaware of which treatment is being given, then they are said to be ‘blind to' the treatment allocation process. If neither the patient nor the doctor is aware of the treatment allocation then the process is said to be a double-blind trial. In such an experiment, one treatment is often a dummy - for example, a pill of the same shape and flavor as the genuine pill, but with no active ingredients. This is called a placebo. In practice, there is often a placebo effect, in which the treated person shows a benefit despite the treatment theoretically having no effect. The effect is a reflection of the psychological benefit of believing that one is being given an effective treatment.