Margin of error
The half-width of a confidence interval — how far an estimate may be off.
The margin of error is the amount added to and subtracted from a sample estimate to form a confidence interval. It captures the random sampling error in a poll or survey: a larger sample shrinks the margin, while a higher confidence level widens it. It does not account for non-sampling errors such as biased questions or non-response.
Example: “52% ± 3%” means the margin of error is 3 percentage points, giving a 49%–55% range.