Clinical Research Glossary

confidence interval confidence interval


The defined range of numbers used to describe where the results are expected to fall.

Example of confidence interval in a sentence

A confidence interval is the range of values that a result is expected to fall in if the test is done again.

More Info

A confidence interval is a measure of variability. It is the likelihood that a measurement, when repeated, will fall within a given range. It can help researchers know how much to trust that a result can be repeated.

The smaller the confidence interval, the more certain the results are.

The term “confidence interval” is often abbreviated as “CI.”

Other info to think about when joining a study

The term “confidence interval” will usually appear in publications about research studies when the article discusses the statistics and results.

The results section may provide more description about the confidence interval as well as define what it is for the specific study written about in the publication.

The confidence interval could also be included in the Plain Language Summary explaining the study results.

An icon consisting of a circle with a calculator, graph paper with a bar chart and a bell curve drawn on, and a pencil. This icon represents all the math terms in this glossary.
This graphic represents math and statistics terms in this glossary.

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