Math Says Yes
Concept

Margin of Error

A margin of error is the plus-or-minus range around a survey estimate caused by sampling uncertainty. If two estimates have overlapping uncertainty ranges, the apparent leader may not be truly ahead.

Lessons

Point estimates shown with horizontal uncertainty ranges.
Uncertainty Needs Ranges
A measured number is usually a best estimate with sampling wobble around it, so honest comparisons need ranges as well as point estimates.

Related Facts

Risk & Decisions
4 min ยท easy
Two poll bars with overlapping margin-of-error brackets.
A three-point poll lead can still be a tie
If a poll says 51% versus 48% with a plus-or-minus 3 point margin of error, the headline leader may not really be ahead.

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