Evidence quality
Publication bias
Distortion caused when positive or striking studies are more likely to be published than negative studies.
What it means
Definition
Publication bias. Publication bias can make a field look more convincing than it is. If small negative studies remain unpublished, reviews and news stories may overestimate benefit.
What it can tell you
It can help clarify what sort of evidence or claim is being discussed.
What it cannot tell you
It cannot, by itself, prove that the headline is accurate or clinically important.
Headline trap
Why this matters in headlines
A supplement may look promising if only favourable trials reach journals.