Country polling guide

Spain polling guide

A guide to Spanish national vote-intention polling, province-based proportional seats, regional parties, alliance changes and the local balance.

Last reviewed 9 Oct 2026

Open Spain tracker

Overview

The Spanish tracker compiles published nationwide voting intention for general elections while retaining regional-party and other categories where the source reports them. It is a national evidence series and does not translate a poll directly into the composition of the Congress of Deputies.

Electoral system context

Congress seats are allocated mainly by proportional representation within provinces, using district-specific lists and allocation rules. Minimum provincial representation and varying district magnitudes make support in smaller provinces consequential and can produce seats that differ from a simple national proportion.

Party and bloc rationale

The local balance groups PSOE, Sumar, Podemos and IU against PP and Vox. Regional parties, Ciudadanos and others remain outside because their position and electoral role cannot be represented responsibly by one binary value. The grouping is local navigation, not an official or international scale.

The current source layout counts PSOE, Sumar and Podemos. IU is represented inside Sumar rather than added again as a standalone estimate; historical IU observations remain separate. See [IU’s Sumar statement](https://izquierdaunida.org/2023/07/10/manifiesto-en-apoyo-a-sumar/).

Polling limitations

Alliance brands and components change, pollsters differ in whether they report coalitions or constituent parties, and regional support is compressed in a nationwide table. Province-level allocation, turnout and territorial concentration are outside the chart, while archive gaps and missing values remain unbridged.

Bloc summaries use complete paired polls within 45 days of the latest archive record, weighted by recency and sample size. Both sides use the same eligible polls. The tracker and map show the number of complete polls and their supporting date, which can precede the latest archive record; missing parties are not assigned zero. The comparison’s latest-poll balance is a separate individual observation.

Sources