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Types of Clinical Trials – Based on Blinding
What is Blinding?
A procedure in clinical trials by which one or more parties are kept unaware of the treatment assignments. i.e. Based on the types of blinding, people will be unaware of which patient is getting which treatment. The treatments will be similar looking and will contain only codes and not names. This is typically done to avoid bias.
Bias may occur when either the investigator or the subject knows which treatment is being given. The investigator’s observations and judgements may become less objective and the patient’s responses may become more positive or more negative depending on whether or not he is in the active treatment arm of the study. Therefore, clinical trials should use the maximum degree of blindness that is possible, so that patients or both patients and investigators are unaware of what treatment has been given.
- In OPEN LABEL CLINICAL TRIALS, the investigators and patients know what treatment each patient is
- In SINGLE BLIND CLINICAL TRIALS, only the patient is unaware of the treatment.
- DOUBLE BLIND CLINICAL TRIALS means that neither the patient nor the investigator is aware of the
treatment. This is the most desirable method to prevent assessment and response biases.
- In TRIPLE BLIND CLINICAL TRIALS- patient, investigator and also the data-monitoring body are
unaware of the treatment group.
- In DOUBLE DUMMY TECHNIQUE is used for drug trials comparing two active treatments, e.g. each patient receives one of the active tablets and a dummy tablet that looks like the alternative active tablet.