The concept of strategic voting is widely used by political parties and the media since the beginning of the campaign. It is assumed that it is a widespread behaviour because Canada has a "winner-takes-all" electoral system. But what do we really know about strategic voting? Beyond anecdotal features and conventional wisdom, social scientists have actually taken this issue seriously -- at least since the 1988 election. Based on the literature, I propose to revisit three common myths that are ubiquitous and will probably persist during the actual campaign.
To do so, we need to define rigorously what a strategic vote is. There are two very simple conditions for a vote to be qualified as strategic: first, a voter must not vote for her preferred party, and second, behave this way in order to block a worse option. As we shall see, this straightforward definition has enormous consequences when it comes to quantifying strategic voting.
Most people are potential strategic voters
The most basic prejudice that we hear is that most people are potential strategic voters, while in fact, it is not the case. Following our definition, potential strategical voters are only those who are in a district where their preferred party is not expected to be in the top two most likely candidates to win. Indeed, why would a voter act strategically if her preferred party (candidate) is expected to win or is the second most competitive option?
Potential strategic voters are thus citizens that have a sincere preference for a candidate that is not in the top two contenders. The logical consequence is that the size of the electorate that will have an incentive to desert strategically goes down to barely 20 per cent to 25 per cent (according to the Canadian Election Study data). This decrease can mostly be explained by a partisan bias which results in an overestimation of the likelihood of the preferred party's candidate winning.
For example, a conservative in a Quebec district might have an incentive to act strategically by voting for the liberals in order to block the NDP candidate, but because of the overestimation, the voter doesn't think herself as a potential strategic voter. In sum, there are fewer Canadians that will really need to ask themselves if they should desert their preferred option.
Strategic voting has a big impact on the electoral outcome
Even if one agrees that strategic voting is not an objective option for most voters, it might, at the end of the day, have a significant impact on the electoral outcome. This is the second feature that is often exaggerated in the public sphere.
As there are far fewer potential voters than expected, it is simply logical that the proportion of actual strategic voters decreases. In fact, even if it is framed in an impressive way, say 30 per cent of potential strategic voters decide to coordinate in order to block a worse option, it would results in 30 per cent of those potential strategic voters -- which represents about 6 per cent of strategic voting.
This percentage is divided mostly among the Conservatives, Liberals, NDP and the Bloc Québécois (in Québec), which means that the odds of the impact of strategic voting to be pivotal on the outcome is very small. Still, we need to admit that in a tight horse-race, it might have a greater impact than expected, but as do others factors such as the party's branding, performances during debates, etc.
Hence, we can question the relevance of the NDP's spin that encourages voters that might not vote for the NDP to do so in order to whip out a worst option (i.e. the Tories of Stephen Harper) and take the office for the first time. Spin doctors (of all parties) generally have a very good political intuition, but when it comes to encouraging people to do some strategic calculus, taking a look at the unanimous literature on strategic voting might have been useful.
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