Confidence interval
A range showing how precisely a result has been pinned down.
Learning
What it means
A confidence interval gives a range of values consistent with the data. A wide interval indicates a lot of uncertainty; a narrow one indicates a more precisely estimated result.
Why it matters if you take part
The width matters as much as the headline number. A large apparent benefit with a very wide interval is a weaker finding than it first appears.
Related terms
This explains how clinical research works. It is not medical advice and does not describe any specific condition or treatment. Only a trial site can determine whether someone can take part in a study.