I’ve heard this term used before with regards to studies and experiments, but I’m not sure what it means. Does it mean that the people administering the experiment don’t know whether groups get placebos or treatments until after the test is complete?
Yes, double blind means neither the people taking nor the people distributing the treatment knows who is getting the treatment and who is getting the control.
Thanks!
Also the people evaluating the outcomes don’t know either. Only at the end is all revealed.
So, in which field are double blind tests commonly used? Medical research? I can’t recall reading any detailed descriptions of actual double-blind tests.
Here is some information about the double blind trial used to determine the efficacy of St. John’s Wort.
Medical research is the one you hear about most. The patients might be divided into two groups. One group gets a new drug, the other gets a placebo. Neither the patients, doctors, evaluators or anyone who can influence the outcome knows which group is getting which treatment.
Also used wherever there is a possibility that experimenter bias may influence the outcome of the experiment. Also useful where the experimenters have a personal interest in the experiment’s outcome (example: psi testing).
Note that in medical research, there is often a way to determine which is being given if an emergency should arise and this knowledge become important. One such test that I’m working on has a big peel-off sticker in the patient’s data folder, sort of a “break glass in case of emergency” thing in that you can tell if someone’s looked.
Yes, good medical research uses double-blind studies all the time. Although it can be much harder to do double-blind studies in certain cases, you should always place a certain amount of mistrust in a medical report that does not mention them.