Owen Winter estimates the effect of progressive party cooperation in the 2022 local elections. His evidence suggests a significant increase in the Labour and the Liberal Democrat vote when they were the only progressive parties standing against the Conservatives in a ward, and that the Liberal Democrats were bigger beneficiaries of cooperation than Labour.
The 2022 Local Elections were disastrous for the Conservatives. The party lost almost 500 councillors across the UK, retreating in England, Scotland, and Wales – battleground councils and strongholds alike. Conservative councillors were lost in all directions, with Labour, the Liberal Democrats, and the Green Party all making significant gains. One factor in the success of these parties was electoral cooperation. In many wards in England and Wales, where plurality voting is used to elect councillors, explicit or implicit deals were struck between ‘progressive’ parties to shore up support or oust Conservative councillors. In many cases, this involved a single candidate from Labour, the Liberal Democrats, or the Green Party standing unopposed to maximise gains from the Conservatives.
Estimating the effect of cooperation of this sort is difficult. For a start, local ‘stand-asides’ are often secretive, to avoid the criticism of a ‘stitch up’ or the ire of central party organisations which encourage candidates to stand in every ward. In other cases, seeming collaboration is accidental, with local parties simply not having the resources or volunteers to stand candidates in every ward. A further difficulty is that local cooperation is itself a product of electoral conditions, complicating any attempt to find a causal effect. To control for these issues, I use Coarsened Exact Matching (CEM).
CEM is relatively intuitive: it is a way of comparing data which is almost identical in all regards aside from the effect we are testing. Data is ‘coarsened’, so continuous variables can be placed into categories, and data points which are an exact match are compared. For this research, my data comes from two main sources: election results from Democracy Club’s open-access API and aggregate census demographic data from InFuse by the UK Data Service. The sample is limited to England (due to the relative lack of candidates from all parties in Wales) and to those wards which were contested with the same boundaries in both 2018 and 2022. The data is ‘matched’ by 2018 vote share of the Conservatives, Labour, Liberal Democrats, Greens, independents, UKIP and ‘others’; the percentage of residents born in the UK, retired, white, not deprived, who live in privately rented accommodation, and who have no qualifications. For each variable, the data is coarsened into 10% categories (0-10%,10-20% etc).
For example, in Norton Canes ward in Cannock Chase, Labour was the only ‘progressive’ party standing in 2022. Norton Canes was a narrow Labour win over the Conservatives in 2018, is over 90% white, and less than 10% of people privately rent. The results in Norton Canes are compared against Codnor and Waingroves in Amber Valley, Whitton in Ipswich, and Wakefield West in Wakefield. Each of these wards were a narrow Labour win vs Conservative in 2018, over 90% white and less than 10% private rent, but in these three wards the Liberal Democrats and Greens also fielded a candidate. This does not necessarily mean there was a formal deal in place, but it allows us to see the effect of a sole ‘progressive’ candidate.
The results of this analysis (plotted below) are striking. As one would expect, the estimated result is an increase in vote share for all other parties. The mechanical effect of fewer candidates would suggest this. However, this effect is not even across parties. Labour and the Liberal Democrats both have statistically significant increases in vote share, with central estimates of 6.1% and 14.1% respectively. These estimates are much higher than that for the Conservatives (2.9%), implying that having a single progressive candidate provided a significant advantage for that party. The largest estimated effect here is for the Green Party (14.5%) but the sample of wards where the Greens provided the only ‘progressive’ candidate is far too small for this effect to be significant.
Using the same method, we can see how the effect of a single progressive candidate on the Conservative vote share varies depending on which progressive party is standing. The Conservative vote is estimated to have a significant increase when Labour is the sole progressive party standing (3.9%) while the central estimate for when the Liberal Democrats are the sole party is slightly lower (1.3%).
These results suggest several tentative conclusions. All estimates here are subject to relatively large confidence intervals, but we can see a significant increase in the Labour and the Liberal Democrat vote when they are the only progressive parties standing in a ward. The estimated increase for these parties is larger than the corresponding increase for the Conservatives, suggesting that most voters who would otherwise have supported other progressive parties transferred to the sole progressive party standing.
The results also suggest that the Liberal Democrats are bigger beneficiaries of cooperation than Labour, with a larger increase in vote share and smaller corresponding effect on the Conservative vote when the Liberal Democrats are the sole progressive party. This might be because Liberal Democrat voters are more evenly divided between supporting Labour or the Conservatives when there is no Liberal Democrat candidate, while Labour voters split more heavily in favour of the Liberal Democrats. The effect sizes identified are relatively small, but given the narrow margins in many electoral contests, they are not to be sniffed at.
These findings should not be directly transferred to Westminster or other elections. With low turnout, local election voters are not representative of the public. They are likely to be ‘high engagement’ voters and therefore more likely to transfer predictably between progressive parties. Local elections are also more heavily dependent on on-the-ground campaigning, so the redirection of resources afforded by standing down candidates will likely yield more significant effects. On the other hand, the increased (negative) partisanship associated with General Elections might increase the effectiveness of progressive stand-asides, as opposition voters are corralled to oppose the Conservative government.
Caveats aside, this research shows how electoral collaboration can have a significant effect on election results. When only one progressive party stood in a ward, voters were more likely to support other progressive parties than the Conservatives. Further collaboration could cost the Conservatives dozens of councillors in future.
Note: Full replication data and code is available here.