Help please!

[tobe38]

I'm doing some research for an article on my blog, and I just want to be clear on something:

In a medical trial, is a control group used instead of a placebo, or along with it? If they are not used together, why not? Why would we use one, but not the other? Am I right in thinking that the difference between the two is that the control group knows that they've not had anything, whereas the people who have had a placebo (and the testers) don't know that they've not had a real drug?

Would appreciate any help. Thanks.

[doghouse]

IIn a medical trial, is a control group used instead of a placebo, or along with it? .

The placebo group is the control group.

However, not all studies have a placebo group, in which case you might use another type of control. For example, you might compare a new treatment to a standard treatment (control group).

Why would we use one, but not the other?

First of all, not all medical studies are treatment studies, so a placebo is not always necessary. But even in treatment groups, a placebo may not be desirable. For example, if there is an established treatment for a disease it may not be ethical to withhold treatment in leu of a placebo.

In general though, using a placebo control results in the strongest type of study.

Am I right in thinking that the difference between the two is that the control group knows that they've not had anything, whereas the people who have had a placebo (and the testers) don't know that they've not had a real drug?

Blinding is a little bit different than the issue of a placebo. For example, you could have a trial in which one group knows they are getting the placebo. And you could have a study in which one group gets an active treatment, another group gets a new treatment and yet neither knows which they are getting -- it's still blinded.

But again, using blinding generally results in a stronger study because it removes some types of bias.

However, blinding is not always possible. For example, blinding is difficult in studies of surgical techniques.

[Loren Pechtel]

A placebo is one type of a control. In some cases the control is the standard treatment for the condition.

As much as they can they keep people from knowing what was used, although in some cases that's impossible.

[tobe38]

Thanks! :notworthy:

If anyone's interested, I've not posted the article here (http://aloadofbright.wordpress.com/2007/05/09/the-control-group/).