[vidarh]

A control group that does not do anything and does not receive anything is not using a placebo.

A placebo is very specifically a substitute for whatever you want to measure the effect of.

You can have both a control group and a group using a placebo and get substantially different results for them, and that's exactly why placebos are used: People report substantial effects from sugar pills and the like when they believe there should be an effect.

[return0]

well yeah , you would then have to have a "sugar pill" group. I wonder whether these studies include an third" no intervention" group.