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Clinical Trials

The Clinical Trials blog has now been retired. We appreciate the wisdom and support Joe Giffels, MAS has brought to the WebMD community throughout the years. You can read about clinical trials here. And if you’d like to talk to others, drop into our Health Café message board.

Wednesday, December 14, 2005

The Blind Study
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Most clinical trials can be improved by designing them as blinded, rather than non-blinded studies. Perhaps not the most PC description. "Blinding" simply refers to the fact that, during a study, the investigator or the participant or both are not aware which one of two or more experimental procedures the participant is undergoing.

Let's say I have volunteered to participate in a clinical trial of a new diet pill (not that I need to lose weight, you understand!). The study is set up such that I could be randomly put into any one of three experimental groups. If I'm in Group 1, I would take one capsule containing the new diet drug. If I'm in Group 2, I would take a similar-looking capsule which contained an existing diet drug. And if I'm in Group 3, I would take a capsule containing an inactive powder (a placebo). By comparing results of the three treatment groups, the investigators hope to draw some conclusions about how effective the new diet drug is.

If I am not told which Group I am in, then I am said to be "blinded," and the study is called a "single blind" study. If neither I nor the investigator who is taking measurements (such as my weight and waist size) during the study knows which Group I've been put in, then the study is said to be a "double blind." Of course, the study team has records showing which Group I was in, and I will be told which Group I was in when the clinical trial is finished.

I'll discuss why such blinding is important to many clinical trials in a future blog.

-Joe

Related Topics: Informed Consent, Clinical Trials Quiz

Posted by: Joe Giffels_ WebMD at 1:31 AM

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