Why Early EU Election Projections Can Mislead
Early projections for European Parliament elections carry more uncertainty than their national counterparts. When polling begins a year or more before election day, several factors distort the picture: national polling is often conducted without explicitly referencing the European Parliament election, meaning respondents may be expressing a general political preference rather than an EP-specific voting intention. Turnout assumptions are particularly problematic — EU election turnout differs substantially from national election turnout, and models that use national turnout as their baseline consistently overestimate support for parties whose voters are more likely to abstain in lower-salience European contests.
The result is that early projections frequently show the S&D — the centre-left group — in stronger polling position than the eventual result, because Labour, PSOE and other social democratic parties tend to have higher levels of nominal voter identification than actual EP election turnout among their core supporters. As election day approaches and models incorporate EP-specific turnout estimates, the EPP typically recovers its structural lead.
The S&D in Early European Parliament Polling
The Progressive Alliance of Socialists and Democrats — the S&D group — draws its strength from the major social democratic parties of the largest member states: Germany's SPD, France's Parti Socialiste (before its fragmentation), Italy's PD, Spain's PSOE, Romania's PSD and Poland's PO (when the latter was classified as centre-left). When these parties poll well in domestic surveys, early EU election projections can show S&D matching or leading the EPP in seat estimates.
However, EP elections expose the S&D to a persistent structural disadvantage: the EPP's affiliated parties tend to be more dominant in smaller member states, which — due to the minimum seat floor — are overrepresented relative to population. This means the EPP converts a similar vote share into more seats than the S&D would. Early projections that apply simple vote share-to-seat calculations without accounting for this structure tend to be more favourable to the S&D than the final result.
How Projections Evolved Across Campaign Cycles
Tracking how EU election projections change from the first estimates to the final result reveals consistent patterns. In cycles where the European economic situation was politically salient — particularly during and after the eurozone crisis — support for mainstream centre-left parties was initially overestimated, while support for eurosceptic and populist parties was underestimated because smaller parties are harder to poll precisely across 27 countries.
The most informative comparison is between projections produced 12 months before election day and those produced in the final week. This comparison typically shows convergence toward the final result as country-level polls become more frequent and EP-specific, and as analysts refine their group affiliation assumptions for parties whose European allegiances are in flux. The post-election reshuffle then adds another layer of uncertainty that no projection can fully anticipate.
Forecast Accuracy and Its Limits
The most accurate EU election forecasts combine several inputs: national polls from each member state, weighted by recency and pollster track record; EP-specific turnout models calibrated against historical data; group affiliation probabilities for parties in transition; and seat-to-population adjustments for each country's share of the 720 total seats. Even with all of these inputs, forecast errors of 10–15 seats per group are common, and errors at the national delegation level can be considerably larger.
This uncertainty is not a failure of methodology but a reflection of the genuine unpredictability of EU elections. With 27 simultaneous national contests, each with its own political context, unexpected outcomes in one or two large member states can shift the aggregate result significantly. The lesson for consumers of EU election projections is to focus on ranges rather than point estimates, and to pay particular attention to which assumptions drive the model's output.
EU Election Results and Governing Coalitions
The importance of accurate EU election forecasting extends beyond the curiosity of getting the seat count right. The balance between the EPP, S&D and Renew Europe — the three parties of the governing coalition — determines whether that coalition maintains a working majority for the five-year term, and by how much. A coalition that enters the term with a comfortable majority of 40–50 seats can afford occasional defections and votes with the Greens or ECR. A coalition that enters with a majority of 10–15 seats requires almost constant unity and is more vulnerable to policy concessions demanded by potential swing votes.
Understanding the trajectory of early predictions — and the reasons they diverge from the final result — is therefore essential context for anyone trying to understand how European Parliament elections shape EU policy outcomes.
Frequently Asked Questions
Why do early EU election predictions often favour the S&D?
Early predictions often favour the S&D because they are based on national polling that reflects general political sentiment rather than EP-specific voting intentions. Social democratic parties typically have higher nominal voter identification than actual EP election turnout among their supporters, so models that apply national poll shares without EP-specific turnout corrections tend to overestimate S&D performance relative to the final result.
How accurate are EU election seat projections?
EU election seat projections typically carry uncertainty of ±10–20 seats for major groups when produced months before election day. Projections produced in the final two weeks are more accurate, but errors of ±5–10 seats per group remain common due to the difficulty of aggregating 27 separate national polling environments with varying sample quality and frequency.
How many seats does the S&D group have in the European Parliament?
Following the 2024 elections, the S&D group holds approximately 136 seats in the 720-seat European Parliament — the second-largest group after the EPP. This represents a relatively stable position compared to recent terms, as the major losses in the 2024 cycle were concentrated in the Greens and Renew Europe rather than the S&D.
What is the difference between European election results and projections?
European election results are the official certified seat counts for each political group, determined by counting votes across all 27 member states and applying each country's electoral rules. Projections are estimates produced before the vote, based on polling data. Results are also confirmed only after MEPs formally declare their group membership in the constitutive session, which can differ from pre-election group assumptions.
What drove the S&D's performance in the 2024 European elections?
The S&D maintained a relatively stable position in 2024 despite the broader rightward shift of the EP. Strong performances by PSD in Romania and PSOE in Spain offset weaker results elsewhere. The group's final seat total was broadly in line with late projections, confirming that the S&D structural base — anchored in southern and eastern European social democratic parties — remained resilient.
How do EU election results compare to national election results in the same countries?
EU election results often diverge from concurrent national polling because EU elections tend to be "second-order" contests — voters use them to express protest against governing parties or to support niche parties they would not back in a national election. Turnout is lower, which changes the composition of the electorate; governing parties tend to underperform their national poll ratings; and smaller parties often outperform their typical national share.