1 election where the final polls got the result badly wrong. Each deep dive sets out what the polls said, what happened, what the official inquiries and the pollsters found, what our own data shows, and what the pollsters changed afterwards. Every one of these misses is in the record our forecasts learn from.
How far out the final polls were
The error on the lead between the top two: the final polls' average against the result, in points.
Every final poll had Bronisław Komorowski about ten points ahead of Andrzej Duda; Duda came first by one point and Paweł Kukiz beat his polls by five. Turnout of 49% and a late break away from the incumbent undid polls that assumed a much larger, steadier electorate.
For each country we measure how far the final polls missed at past elections. We take half the average miss off today's polls only where that would have made past forecasts better, testing each election without knowing its result; elsewhere the polls stand as published. Every forecast then runs thousands of simulated elections with polling errors the size of these, so a miss like the ones above is inside our ranges, not a surprise. Polls against results, every election · Our forecast record · Pollster leaderboard
Poland · 10 May 2015
11.0 pts