The process used to prevent (conceal) advanced knowledge of what intervention group people have been assigned to in a randomised controlled trial. It should be done by someone who is not responsible f [..]

Randomization is concealed if the person who is making the decision about enrolling a patient is unaware of whether the next patient enrolled will be entered in the intervention or control group (using techniques such as central randomization, or sequentially numbered opaque sealed envelopes). If randomization is not concealed, patients with differ [..]

Occurs when the person who is enrolling a participant into a clinical trial is unaware whether the next participant to be enrolled will be allocated to the intervention or control group.