A Bayesian poll-of-polls for the Sejm: voting intention since January 2025, seat projections for every week, polling-house effects, and a scenario builder for vote shares, joint lists and government options that keeps the model’s uncertainty.

Fragmentation, disproportionality, volatility, nationalisation, polarisation and the closure of government competition for every Sejm election since 1991 and for the current polls, with the lists, lineages, party positions and cabinets behind each number.

The lifespans, Sejm seats, government status and genealogy of every party that has sat in the Sejm since 1989: the splits, mergers, renames and alliances that link them. Trace any party’s predecessors and successors.