Assertion: placebo's study | /r/HasAspect | untreated groups
Facets:
value: in order to distinguish the placebo effect
type: PURPOSE
Source sentences:
text: Most studies have attributed the difference from baseline until the end of the trial to a placebo effect, but the reviewers examined studies which had both placebo and untreated groups in order to distinguish the placebo effect from the natural progression of the disease.