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Quebec 2018: A Failure of the Polls?

Published online by Cambridge University Press:  06 December 2019

Claire Durand  and
André Blais
Claire Durand*
Affiliation:
Département de sociologie, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, H3C 3J7
André Blais
Affiliation:
Département de science politique, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, H3C 3J7
*
*Corresponding author. E-mail: Claire.Durand@umontreal.ca
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Abstract

The polls of the 2018 Quebec election forecast a close race between the two leading parties. The result, a clear victory of the Coalition Avenir Québec (CAQ) over the Parti libéral du Québec (PLQ), was clearly at odds with the polls. We argue that when the polls get it wrong, it is important to determine whether there was a polling miss, in which the discrepancy is due to changing voter behaviour, or a poll failure, in which the problem stems from polling methodology. Our post-election poll shows that changing voter behaviour—last-minute shifts and the vote of non-disclosers—explains most of the discrepancy. These movements varied by region. We conclude that the Quebec 2018 election was among the worst polling misses in history but not necessarily a major poll failure.

Résumé

Résumé

Les sondages de l’élection Québécoise de 2018 avaient annoncé une lutte serrée entre les deux principaux partis. Le résultat, une victoire décisive de la Coalition Avenir Québec (CAQ) aux dépens du Parti Liberal du Québec (PLQ), n’était clairement pas ce qui avait été anticipé. Nous soutenons que, lorsque les sondages se trompent, il est important de déterminer si l’écart entre les estimations des sondages et le vote est dû à un changement dans le comportement des électeurs ou à un échec des sondages eux-mêmes attribuable à la méthodologie utilisée. Notre sondage post-électoral montre que des changements dans le comportement des électeurs—changements de préférences de dernière minute et vote des discrets—expliquent la majeure partie des écarts dans cette élection. Ces mouvements varient toutefois selon les régions. Nous concluons que l’élection québécoise de 2018 se situe historiquement parmi les pires écarts entre les sondages et le vote mais ne peut pas être considérée comme un échec majeur des sondages eux-mêmes.

Keywords

poll failurepolling missQuebec 2018 electionlate campaign shiftéchec des sondageserreur des sondagesÉlection Québec 2018changement de fin de campagne
Type
Research Article/Étude originale
Information
Canadian Journal of Political Science/Revue canadienne de science politique , Volume 53 , Issue 1 , March 2020 , pp. 133 - 150
Copyright
Copyright © Canadian Political Science Association (l'Association canadienne de science politique) and/et la Société québécoise de science politique 2019

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