Sampling and Non Response Bias in Electoral Surveys, The Case of the Quebec 1998 Election (original) (raw)

Accounting for Biases in Election Surveys: The Case of the 1998 Quebec Election

During the last electoral campaign in Quebec, Canada, all the polls published in the media had a similar estimate of vote intentions, putting the Parti Quebecois (PQ), a centre-left party dedicated to Quebec sovereignty, clearly ahead, by an average of ®ve points in the last six polls of the campaign. The PQ won the election, held on November 30, 1998, but with a smaller share of the vote (43 per cent) than the contending Liberal party (44 per cent), a centre-right federalist party. Pollsters and many observers have maintained that the discrepancy between the polls and the actual vote could be explained either by a last minute shift in favour of the Quebec Liberal party or by differential turnout.

Factors affecting political poll accuracy: An analysis of undecided respondents

Recently, pollsters have experienced discrepancies between their poll predictions and subsequent election outcomes. One possible explanation of these divergencies is the growing proportion of undecided respondents in poll samples. This paper discusses three methods of reducing the proportion of undecided respondents: the use of contextual questions; a secret ballot device; and the use of a relative, rather than absolute, behavioural question. It concludes that, although it is possible to completely eliminate this group from poll samples, reductions in the proportion of undecided respondents are not necessarily matched by an increase in the accuracy of the poll estimates. Indeed, this study found that the sub-sample with the highest proportion of undecided respondents also produced the most accurate estimates. The paper concludes that direct intention questions, together with reduced contextual questions, and allocation of undecided respondents in proportion to party support levels, seem likely to produce the most accurate poll estimates.

The Accuracy of Public Polls in Provincial Elections

Canadian Political Science Review, 2015

This study extends work on the accuracy of polls released in the final week of election campaigns in Canada, using data from the nine provincial elections held in Canada between 2011 and 2013 to identify what might affect the accuracy of those polls. Specifically, we attempt to empirically test two arguments - mainly that some methodologies are better than others in measuring voter preferences and that the nature of the election itself might make accurate forecasts more difficult. We find that absolute change in voter turnout was the strongest predictor of polling accuracy. In contrast, sample size, survey mode, or electoral volatility were statistically significant predictors of polling accuracy.

Lost on the Way: Nonresponse and its Influence on Turnout Bias in Postelection Surveys

International Journal of Public Opinion Research, 2015

Earlier studies on turnout bias in postelection surveys have focused on vote overreporting (measurement bias) and have disregarded nonresponse bias associated with voter overrepresentation. Based on a unique data set of validated votes collected for two different ballots, we offer an in-depth analysis of the size and sources of nonresponse bias. On the aggregate level, we find that voter overrepresentation accounts for a larger share of total turnout bias than misreporting. On the individual level, past voting record, ballot vote, and age appear as strong predictors of survey participation. Breaking down further the analysis, we show that these factors contribute to nonresponse bias through both contact and cooperation. By contrast, the effects of some other factors work at cross-purpose in the contact and cooperation stages.

The 2000 Canadian Election and Poll Reporting under the New Elections Act

Canadian Public Policy / Analyse de politiques, 2002

Just before the 2000 Canadian electoral campaign, a new law was passed regulating the publication of polls in the media during electoral campaigns. The law required newspapers to publish basic information about the way the polls they presented were conducted, and the wording of questions and the means by which a methodological report could be obtained. In addition, the law specified which information the methodological report must contain. This article examines the extent to which the law was complied with. The research shows that the first two points were not problematic, though sometimes the information was not easily available. However, methodological reports did not generally provide all the requested information. In particular, crucial information such as response rates, refusal rates and the sampling method used were rarely provided. It would also appear that compliance with the law was not verified. Elections Canada relied on the public to issue complaints, and the media relied on pollsters to provide the information. The study concludes first, that ambiguities in the Act concerning exactly what information is required should be clarified; second, that methodological information should be placed together in a separate and identified subsection, as was the case with most media reports; and third, that Elections Canada should provide a model of the detailed report (326-3) so that the media and pollsters all present the information in a standard, easy-to-compare fashion.

Closeness Counts in Canada: Voter Participation in the 1993 and 1997 Federal Elections

Journal of Politics, 2002

Theory suggests that eligible voters should be more likely to cast ballots when election margins are close. Empirical evidence, however, is mixed. Operational definitions of key concepts such as turnout and election closeness are often inconsistent and limited in application to two-party systems. This paper provides a more generalized test of the turnout-competition link in electoral districts. Data are 1993 and 1997 constituency-level election results for the Canadian House of Commons. Canada provides an excellent case for comparison because it has single-member districts, plurality elections, both national and regional parties, and multiparty competition throughout the nation. Several alternative measures for "turnout" and "closeness" are evaluated in the context of multiparty elections. A new index of competitiveness is developed. Multicandidate measures of closeness are related to higher levels of voter participation in Canadian federal elections.