Imagine the following:
A drug company promoting a drug for back pain conducts a blinded clinical trial in which patients receive either 1) the drug, 2) a placebo sugar pill that looks the same as the drug or 3) nothing. The results from the trial show that patients who receive both 1 + 2 show more relief from back pain than those receiving no treatment but there is no significant difference between the effect of the placebo pill and the real drug.
Now imagine a newspaper article reporting on the research chose the headline ‘Scientists find new drug can help to relieve chronic back pain’ followed by a glowing report of how the drug has proven to be effective in treating back pain complete with pleased quotes from the trial authors.
See the problem here? The drug was proven in a clinical trial to be no more effective than an inert sugar pill and yet it is being promoted in the newspaper and by the trial authors as if the trial showed that it is an effective treatment.