Study design
Placebo-controlled trial
A trial where one group receives an inactive comparison treatment.
What it means
Definition
Placebo-controlled trial: A placebo-controlled trial helps separate the effect of an intervention from expectation, natural recovery, and trial participation effects.
What it can tell you
It can show how close the evidence is to a real human health outcome.
What it cannot tell you
It cannot prove that a treatment works in people unless human outcome data are available.
Headline trap
Why this matters in headlines
A pain treatment tested against placebo is more informative than a treatment tested with no comparison group.