Answer:
Clinical trials are a form of research, used mostly in the medical sciences, that allow professionals and researchers to study the impact that a particular pharmacological treatment, or other forms of clinical treatment, may have on a patient, a group of patients, or society at large.
In order for them to be accepable by authorities, these studies must have certain regulations, that will show the purpose and final goal, of the research being carried out.
As such, we have two types of research: the single-blind, and double-blind, and we also have the use of "placebo", on these trials.
First, lets define placebo. Placebo is used in research as a substance that replaces the actual treatment, but has not actual effect on the condition, or circumstance under study. Usually, they tend to be called as sugar pills. In research, a group of candidates is selected usually to receive this form, so that there can be a comparisson with the group that is actually receiving the true treatment.
The single-blind method of research is in which researchers know how the treatment and placebo will be distributed to the candidates of the research study, and have a certain level of control. They cannot assign the members however they like to either group, there must be a limit, otherwise it would be a biased study, but the researchers knows which group gets what treatment.
In the double blind method, both the researcher team, and the candidates, do not know who is getting either the placebo, or the actual treatment.
