Spain: Polling data and insights by 40dB

The PolitPro election trend serves as the reference value and represents a time-weighted average of current opinion polls. A poll result is classified as higher or lower if it differs from the trend by more than one percentage point.

Election accuracy shows how close pre-election polls were to the actual election result. We compare an institute’s pre-election polls with the final election outcome. For each election, we calculate the average deviation of party results and then compute an overall average. Only parties with an election result of 3% or higher are included. Opinion polls generally have a margin of error of 2–3 percentage points. Average deviations of up to 1 percentage point are rated as very good (green), up to 2 percentage points as good (yellow). Deviations of up to 3 percentage points are rated as ok (orange) but already show clear outliers for some parties. Average deviations above 3 percentage points indicate weaknesses in accuracy and reliability and are rated as poor (red).