Although the existence of strategic voting in the United Kingdom and Canada has been well documented, quantifying when a voter will cast a strategic ballot has yet to be done. This article draws on electoral data from five UK and Canadian elections in order to address this gap by identifying a precise “tipping point” for when a non-viable party supporter's probability of voting strategically crosses a 50 per cent threshold. I find the best tipping point measure occurs when a voter rates their favourite viable party greater than 59 out of 100 in the UK and greater than 73 out of 100 in Canada. Both countries also have clear tipping points for the likeability of an individual's highest preferred party and perceptions of that party's distance from contention. Overall, by calculating these tipping points, researchers can better gauge voter behaviour and how, or when, certain factors contribute to strategic voting.
