Tremors But No Youthquake: Measuring Changes in the Age and Turnout Gradients at the 2015 and 2017 British General Elections
22 Pages Posted: 6 Feb 2018
Date Written: January 28, 2018
A common belief about the 2017 UK General Election is that Labour did unexpectedly well because of a surge in youth turnout. Constituency data appeared to support this claim: the increase in turnout from 2015 to 2017 is correlated with the number of young people in a constituency. Various polling estimates have been put forward for the size of this ‘youthquake’, ranging from a 12 point increase in turnout amongst the youngest age group to a 19 point increase. In this paper we show why these claims are wrong. We show why the aggregate relationship is likely to be spurious and is driven by the types of places young people live, not the behaviour of young voters. We also show how representative samples of voters and non-voters, properly weighted, reveal a very different conclusion. To examine the relationship between age and turnout in 2015 and 2017 we use the best available survey data, the British Election Study face-to-face surveys. We also provide methods to overcome three challenges in gaining accurate measures of turnout: 1) gathering accurate targets so as to accurately adjust the survey for demographic imbalances due to differential response rates 2) adjusting the survey to account for the fact that people who turn out to vote are more likely to take part in surveys; and 3) dealing with the fact that people over-report having voted in elections in surveys. Using these novel analyses we find no evidence of a substantial shift in the relationship between age and turnout between 2015 and 2017.
Keywords: Turnout, Survey weighting, Ecological Fallacy, British politics
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