Undecided voters are less likely to cast their ballot, UK study shows

Undecided voters are less likely to cast their ballot, according to a new study which shows how the fragmentation of the political party system in the UK is fueling low turnout at elections.

The number of citizens undecided in how they’d vote has risen in Western democracies. People are becoming less partisan, meaning they have weaker ties to political parties. There are more parties on the ballot and more voter volatility.

The study, published in Electoral Studies, shows how election participation is lower when citizens are subject to high levels of competition for their vote. People in the electorate are ‘in competition’ when they have similar preferences for more than one party.

Dr. Hannah Bunting, from the University of Exeter’s Elections Centre, found these voters have a ten point lower likelihood of voting than those with a clear political preference. The probability of voting declines from 89.1 percent to 79.2 percent when people are deliberating between two or more parties.

Dr. Bunting said, “Voters are now more indecisive, more likely to switch parties, and generally more volatile and unpredictable in their behavior. My research shows low levels of voting may be related to the more complex choices people have to make, and people becoming more indecisive.”

The British Election Study’s internet panel suggests around 40 percent of voters are undecided. This new analysis shows they are also less likely to intend to vote.

The study says voter turnout improves when people have a partisan identity and pay greater attention to politics.

Dr. Bunting, who used ten years of British Election Study data for the study, said, “This is a positive sign for democracy. Citizens do seem to spend time deliberating between different parties during competitive elections. The expansion and complexity of choice can promote democracy if parties can convince voters to back them before election day.”

The study is also further evidence constituency marginality is not substantially related to individual turnout and partisanship is an important predictor of voting.

At the most recent general election in 2024, polling showed a significant proportion of the British population expressed that they did not know who they would vote for. Turnout at the 2024 general election was the lowest since the 59 percent in 2001.

Dr. Bunting said, “People used to say ‘I’m Labour’ or ‘I’m Tory’ but there are fewer and fewer people with that strong partisan identity now. This is coupled with a greater number of candidates and different types of parties on offer. All of this means people are more likely to abstain from voting. It creates a greater cognitive burden for citizens and this complexity feeds indecision which increases the likelihood of making no choice at all. A high number of undecided citizens may thus result in low turnout rates.”

The study shows people who have a partisan identity have a 29 percent probability of their vote being in competition between parties, whereas for non-partisans this was higher at 54.3 percent.

Those who pay the least attention to politics are 15 points more likely to be in competition than those who pay the greatest amount of attention. Men are less likely to be in competition, as are older citizens. Individual competitiveness is therefore driven by dealignment and low political engagement, alongside age and gender.