What are negative and positive control groups ?
As you know in most of clinical trials placebo is used. A placebo (sugar pill) is an intervention designed to simulate medical therapy but not believed to have a specific effect on the illness or condition to which it is being applied . In this case a placebo group is the “negative control” group which may only differ from the treatment group in one, and only one, aspect namely the applied drug. According to these needs “double blind clinical trials” were designed using a substance (like physiological saline versus morphine) without any specific activity as “negative control”. Positive control group receives standard treatment.
