Why is a placebo group included in clinical trials?

I really need help on this one because it was a question for my home work, Thanks.

The objective is to eliminate the so-called "placebo effect" from the trial.

Some percentage of people given a therapy that they think will help them, will actually get better, at least according to them, even if the treatment they receive is a sugar pill or distilled water.

It also prevents the physicians evaluating results from finding greater benefits for the group given the real therapy if they don't know which one it is.

A committee is normally assigned to monitor the study, and they will know the unblinded results--so that any adverse reactions from the therapy being tested will be reviewed to determine whether the study should be halted on safety grounds.

Because the experimental group is one part of the clinical trial, and you need something to base it on, and something to compare it to. Say it is a trial for a certain drug, if they only did the experimental trial and not the placebo, then how would they know if it actually worked. The placebo trial means that that group did not receive the drug, but like a sugar pill, so some of the people in the placebo trial will act differently because they think they are getting the medication, and the others will act like their normal selves. The people in the experimental group who receive the actual drug would react to the drug in either the positive way, in which the person doing the experiment wants, because that would mean it worked, or they would act like they always did, meaning the drug did not work. It sounds confusing but it really isnt, you just need the placebo group so you have something to compare the experimental group to.

b/c how can you know if the drug is really doing anything unless you are able to compare it to what happens naturally. also sometimes people make get better b/c they think they are being drugged (the mind over matter debate) so with the placebo group you will really be able to tell if it's mind over matter or the drug actually working.

Because you always need a comparison to compare the data to the experimental group. Without the placebo group, what would the data from the experimental group be compared to?

because you have people who take medicine and it doesn't really work, they just psychologically think it works. So they have a group who take sugar pills, and if they report the pill works its like a control group. The test group you don't do anything to.

To remove bias. You have to see how the control group reacts to thinking they are being put on the medicine. This will help determine the true effectiveness of the medicine.

For control purposes