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The Madison Avenue Field GuideA field guide to marketing & advertising, by Brandon Mina

GlossaryMeasurement & AttributionMargin of Error

Measurement & Attribution

Margin of Error

The range above and below an estimate within which the true value likely falls, at a given confidence level.

By Brandon MinaCEO, BrandPilot AIUpdated November 2026

Short answer

The margin of error is the range above and below an estimate within which the true value is likely to fall, at a given confidence level. It reflects uncertainty from sampling. In surveys and experiments, a wide margin of error means results should be interpreted cautiously, while larger samples generally narrow it.