Eight weeks to 29 November: the average, the CIS on its own and seats within ranges

With 54 days to go until the general election on 29 November, the Su Momento polling average puts the PP on 32.6% of the vote, the PSOE on 26.3% and Vox on 18.8%. They are followed by Sumar, on 6.1%, and Podemos, on 3.5%. According to the same average, the lead of the first over the second stands at 6.3 points, and the seat projection derived from it offers ranges that are best read in full, not just from the middle.

The average, updated on 6 October, includes 28 polls from 16 polling firms, the most recent dated 3 October, selected from the 468 listed in the table of published polls. It is weighted by date and sample size, and each firm's house effect is corrected. The CIS is counted separately and has its own section further down.

Over the past month the average has moved in tenths of a point. According to the Su Momento average, the PP is up 0.5 points in 30 days and Vox 0.3, while the PSOE is down a tenth over the same period. In the past week no party has shifted by more than two tenths: the series, now 644 days long, appears to have taken a breather before the campaign.

The gap with 2023

Taking the official 2023 results as a reference, the PP stands in the average half a point below the 33.1% it won then. The PSOE, which secured 31.7%, appears 5.4 points lower. Vox, which ended up on 12.4%, sits 6.4 points higher, and Sumar, on 12.3% back then, 6.2 points lower.

Among the parties with smaller shares, ERC registers 2.1% against 1.9% in 2023, and EH Bildu repeats exactly 1.4%. Podemos and SALF have no 2023 result in these data to compare against, so their difference box is left blank, which is the most honest thing a box can do.

The CIS, in its own column

The CIS barometer of 4 September, with a sample of 4,042, is not included in the average and is shown separately. Its estimate reverses the top two places: the PSOE on 31% and the PP on 25.5%. Vox appears on 16.6%, Sumar on 5.7% and Podemos on 3.7%.

The Su Momento average combines many polls and corrects each firm's house effect, whereas the CIS figure is presented as a snapshot from a single camera, with its date and its sample. Anyone wishing to compare all the series can do so on the polls page.

Seats: medians and ranges

The Su Momento projection converts the average into seats on the basis of the 2023 results by province and 10,000 simulations. At the median, it would put the PP on 135 seats, with a 90% range of 121 to 151; the PSOE on 106, between 91 and 120; and Vox on 65, between 54 and 80. According to the Ministerio del Interior, in 2023 they won 137, 121 and 33 seats respectively.

Further down the table, the ranges carry almost as much weight as the medians. The projection gives ERC a median of 8 seats, between 3 and 13; Sumar 7, between 4 and 13; and EH Bildu 7, between 2 and 10. Junts and PNV share a median of 5, each with a range of 1 to 8. In a province-by-province allocation, a few tenths in the right place can move a seat from one side to the other.

The same projection aggregates two blocs using an identical procedure. PP and Vox combined have a median of 201 seats, with a range of 187 to 217, and a 99.8% probability of an absolute majority in the simulations; PSOE, Sumar and Podemos combined have a median of 116, with a range of 100 to 130, and a probability of 0%. These are model probabilities, not outcome probabilities: the note accompanying the projection warns that it is not a prediction.

Eight weeks leave room for the average to move, and every new poll will feed into the calculation. Anyone wishing to try out other scenarios can do so in the simulator, and the calendar sets out the dates remaining until 29 November. Until then, the figures in this article are what they are: a snapshot as of 6 October, with their margins in plain view.