double blind

     Many medical or clinical trials are performed using the "double blind" method. The researchers recruit people with a particular medical condition to volunteer to be treated with a drug --or with a placebo, commonly referred to as a "sugar pill". This means that some of the research subjects will be given an experimental medicine, and some will be given a pill that looks like the medicine, but is really a harmless (innocuous) substance, of no medicinal value. The subjects, or patients, will not know whether or not they have been treated with medicine or with a placebo. The volunteers know that this is part of the research, and will not be able to report that they feel better simply because they believe they have been treated with medicine. They will be "blind" subjects. The "double blind" part means that the researchers administering the experimental drugs will also not know which is the drug and which is the placebo. When trials were done with researchers who knew the difference, they seemed to offer hints or clues to subjects, and reporting on the effectiveness of the medicine was compromised. So now most research is done using the "double blind" method.