Belgium has very complex political system, which makes predicting elections incredibly difficult. That's why I have started a project called 1830 with the aim of giving people a more complete and detailed look of the Belgian political landscape.
The map lets you explore the projected vote shares geographically, select individual parties, compare projections with the official 2024 election results, and identify municipalities where the projected largest party changes.
We feed our model by combining polling data with other fundamentals; such as PM popularity, unemployment rate, inflation, purchasing power index, etc...
The projected vote share on the municipal level is the most detailed forecast ever released and something we've been working on for a couple of months.
One important caveat: these are not predictions based on polling conducted in each municipality. The model estimates voting intentions at the regional level (Flanders, Wallonia and Brussels). Those estimates are then projected onto current municipal boundaries using the 2024 federal election results as the local geographic baseline.
In other words, the map combines a regional forecast with the existing geographic distribution of votes. Local voting patterns are used to distribute the projected regional changes, rather than being independently forecast for every municipality.
Hope you enjoy it!
Interactive map: https://1830belgium.com/Prognose.html
Data sources:
- Official election results: Belgian federal election of 9 June 2024, municipal-level results published by the Belgian Federal Public Service Home Affairs (FOD Binnenlandse Zaken / IBZ).
- Polling data: Ipsos polls published by Le Soir, RTL TVI, Het Laatste Nieuws and VTM; and polling by ULB and the University of Antwerp, published through VRT, De Standaard and RTBF.
- Historical polling data: Historical Belgian federal polling series, including data compiled in the project's
historisch_2024.json file.
- Geographic data: Current Belgian municipal boundaries for 2025/2026, with a mapping that consolidates the 2024 results of municipalities that have since merged.
Tools used:
Python, NumPy and SciPy for the regional forecasting model. HTML, CSS, JavaScript and SVG for the interactive map. JSON and geographic data files for storing and processing the election results and projections.
Methodology:
The forecasting model combines historical election results, polling data, pollster-specific adjustments, time-weighted trends and additional political and economic factors. The relative weight assigned to polling and these fundamentals changes as the next election approaches.
To create the map, official 2024 municipal results are first consolidated into the current municipal boundaries. The model's regional vote-share projections are then distributed geographically using each municipality's 2024 voting patterns as the baseline. The projected shares are normalized, with votes for parties not explicitly modelled retained in an “Other” category.
The map therefore represents a spatial projection of regional estimates, not independent polling or a separately calibrated forecast for every municipality.
Interactive visualization: https://1830belgium.com/Prognose.html
Project: 1830 Belgium — https://1830belgium.com