Are Election Polls Right? Analysis of the Accuracy of Election Polls Predictions Published in the Press

Abstract

This paper analyses the predictions of the election results for the
Spanish Parliament published in the main Spanish newspapers. To
gauge their degree of accuracy, the distance between the predictions
and the actual results was defined and later assessed by comparing it
with that of the so-called ‘perfect poll’. This ‘perfect poll’ was generated
by a simulation using the proportions of votes actually obtained by each
party. Other issues related to the published polls are also analysed,
such as the relationship between sample size and estimation quality,
and between the error made (by excess or defect) for a party and the
ideological affinity between that party and the newspaper publishing the
survey.