New research: Comparing rates of electoral assent in the recent Irish and UK general elections

Guest Author

Posted on the 26th March 2020

Luke Field is an Irish political scientist specialising in campaigns, elections, and democracy. He recently completed a Ph.D. in Political Science at University College Dublin and lectures in Politics at University College Cork. He tweets here.

Here he launches new research for the Electoral Reform Society on the UK’s December general election and Ireland’s election this February. 

In February, the Irish electorate went to the polls to elect a new set of parliamentary representatives to Dáil Éireann (the Irish lower chamber of parliament).

While turnout was less than in the most recent UK general election of December 2019 (62.9% to 67.3%), comparing the distribution of votes at constituency level among those elected suggests that the Irish electorate – or at least those parts of it who turned out to vote – may have given greater ‘assent’ to their new parliamentarians than was the case in the UK.

When I speak about voters giving ‘assent’, I mean that voters have indicated that they will be satisfied by the election of a given candidate, through including that candidate in their voting choice on their ballot.

It doesn’t necessarily mean that the candidate was the voter’s preferred choice, or even that the voter agrees with or supports all aspects of the candidate’s policy platform; only that the voter has indicated that they would be content for that candidate to hold political office. This might also be termed ‘voter accordance’.

In the UK context, this is a meaningless distinction. The First Past The Post (FPTP) electoral system only allows for assent to be granted to one candidate. There is no option for voters to, say, indicate assent to the election of any other candidate who shares their view on issues such as Brexit: they can only pick one candidate, and that candidate is either elected or not elected.

Consequently, in the single-seat UK constituencies, a single successful candidate provides 100% of the representation with the assent of potentially far less than 100% of the voters. Indeed, as successful candidates need only a plurality of votes (your nearest opponent’s vote share plus 1) to be elected, newly-minted representatives may have been denied the assent of a majority of their voting constituents, as recent ERS analysis on the UK general election showed.

Ireland’s PR-STV electoral system offers a radically different set of outcomes in terms of assent, and we can understand this through the abbreviations on either side of the hyphen.

First, representation is not solely vested in a single representative, but instead distributed (somewhat) proportionately amongst multiple representatives (proportional representation, PR).

Second, voters are offered the opportunity to state their voting preferences sequentially through the single transferable vote (STV). Through the use of the Droop quota, and because the total level of representation includes the assent granted to several candidates, the percentage of voters in a given constituency that has granted assent to at least one of its representatives is all but guaranteed to be a large majority.

Assent in the UK’s December election

Calculating the level of assent granted to the representative of each UK constituency is very straightforward, as we need only look at the percentage of the vote received by each successful candidate. The range of these values is pretty extensive: at the top of the pile, the greatest level of assent expressed in the UK was for the Labour candidate in Liverpool Walton (84.68%). At the other end of the scale is the Sinn Féin candidate in South Down, who received the assent of only 32.4% of voters. The mean level of assent granted across the 650 UK constituencies was 54.35%, while the median value was 53.74%.

A considerable number of UK MPs received assent from less than 50% of voters in their constituency; 229 in total, or 35.2%.

Assent in Ireland’s General Election 2020

The range of assent – support for the winning candidates – expressed in each of the constituencies has Dublin Rathdown at the lower end (69.34% assent) and Dublin South-West at the upper end (90.24%). The mean of these assent estimations was 81.7% and the median was 82.3% [1]: in other words, 82% of voters have at least one representative for whom they voted, a stark contrast to the UK figures.

Comparing Assent in the Elections

 Even at first glance, it seems quite obvious that the Irish constituencies invested much greater assent in their representatives than was the case for the UK constituencies: the average level of assent was 25.35 percentage points greater for Ireland, while the median level was 28.56 percentage points greater. The highest level of assent expressed in Ireland was 5.56 percentage points greater than the UK equivalent, while the lowest level of assent expressed in Ireland was 36.91 percentage points greater than the UK equivalent. 

More than one in three UK constituencies gave less than 50% assent to their representative; in Ireland, only one constituency invested less than 70% assent in its representatives. In total, 618 UK constituencies (95.08%) expressed less assent in their representatives than was the case in Ireland’s least-assenting constituency. By contrast, 12 of the Irish constituencies (30.77%) expressed greater levels of assent in their representatives than was the case in the UK’s most-assenting constituency.

More than one in three UK constituencies gave less than 50% assent to their representative; in Ireland, only one constituency invested less than 70% assent in its representatives. Click To Tweet


In every Irish constituency, a significant majority the electorate ‘assented’ to the election of at least one of their representatives. In the UK, a majority of voters in one out of every three constituencies did not assent to their representative’s election. This is a pretty significant gap in assent on the part of Irish and UK voters. It should be borne in mind that, where error in these findings exist, it mostly comes from the underestimation of assent in the Irish case; in other words, if these findings are incorrect, it is only because the gap is even greater. 

The higher levels of assent in the Irish context are facilitated by both the proportional representation and the preferential ballots offered by the PR-STV system. Neither of these is offered by the UK’s FPTP system. If UK electors are dissatisfied with their parliamentary representation, they may wish to consider whether their electoral system is a factor.

[1] Calculating the assent in Ireland’s general elections is slightly more complicated by comparison to the UK. The reason for this is largely due to the issue of the ‘surpluses’ of successful candidates (the number of votes by which a successful candidate exceeds the quota, which can be transferred to other candidates), which can either over- or under-estimate the level of assent when transferred. There is also the issue of votes accumulated by the final candidate deemed not elected in each election, as there is no way to verify whether any of these ballot papers held a preference for any of the successful candidates (thus leading to a further underestimation of assent). However, it is possible to at least approximate this level of assent.

In order to provide this approximation, I created an upper and lower limit on assent for each of Ireland’s 39 parliamentary constituencies by modelling the surplus issue in different ways. In order to create the estimator of assent that is most comparable with the UK data, I simply take the midpoint between these two limits. While this value does contain some error for the reasons stated above, and probably under-estimates the level of assent in each Irish constituency, it does provide sufficient accuracy to draw some tentative comparisons between the two elections.

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