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Polls

Here I study the Dutch polls. The last elections took place on 22 November 2023. PvdA and GL decided to enter the elections with a common list, and popular former CDA MP Pieter Omtzigt entered them as well with his new NSC party.

My average

My weighted average of the polls is designed to flatten out trends, so that outliers are somewhat ignored, and only persistent trends accepted. It reports a shift of seats relative to current parliament.

The effective number of parties is a measure for the fragmentation of a party system. The highest effective number ever reached in actual elections was 8.5 in 2021.

Parties

See the party profiles for a description of most parties. Below are the ones I never wrote a party profile for.

Current polls

Here’s an overview of the latest poll by each pollster.

The Weight value gives the relative weight of the poll in the calculation of the Now column above. However, the Now column also uses older polls that fall before the second column’s date, so the average isn’t dependent on these last polls alone.

Poll timeline

Coalitions

The coalition tables are automatically generated and may sometimes show weird coalitions. Still, Dutch politics are in such a state of advanced chaos that even weird coalitions may come to look appealing.

A five- or even a six-party coalition is not as remote as it might seem. Not all parties have to send ministers to the cabinet — they can support government from parliament, like Wilders supported Rutte I (VVD+CDA). The left-wing equivalent would be a PvdA+D66+GL government.

Such a minority government would have to come to agreements with other parties that promise to support it. This combination of government parties and supporting parties is likely to be one of the coalitions mentioned here.

I add the likelihood of all coalitions that a party participates in to get at its likelihood to be in government. I do the same for all coalition types and sizes.

Raw data

There are three pollsters in Dutch politics: Ipsos Politieke Barometer, Peil.nl, and I&O Research. Sometimes NIPO/Kantar also releases polls, but they do not believe in reliable timing.

Ipsos and I&O are going to merge. For now, however, they're still publishing separate polls. That might change in the future.

The political TV programme Eén Vandaag used to commission one monthly poll from Ipsos. However, in August it switched to Verian (a new name for TNS NIPO).

Here’s the raw JSON data; below are some nice graphs and tables.

Ipsos Politieke Barometer

Ipsos tended to publish its Politieke Barometer poll on the last Tuesday of the month, but that was before the political TV programme Eén Vandaag switched to Verian (TNS NIPO) as a pollster. Now I don’t know when, or whether, they’ll publish polls.

To make matters more complicates, Ipsos NL merged with I&O. Although in the first half of 2024 the two former pollsters continued publishing separate polls it’s unclear for how long that will continue.

Prior to 2021 Ipsos was clearly the best Dutch pollster, but nowadays that is becoming more questionable. It tends to have better results for the right block and the traditional catch-all parties.

Peil.nl

Peil.nl used to publish its poll every week on Sunday, but now skips many Sundays.

Peil.nl is always out for sensational headlines. Protest parties SP and PVV usually poll better with Peil.nl than with the other two, and the same goes for the left block and for small parties.

Maurice de Hond is Peil.nl’s owner and a well-known political commentator in his own right.

I&O Research

I&O Research publishes a poll each month around the 15th. Their polls tend to over-estimate the left a bit.

I&O is going to merge with Ipsos. Since Ipsos is much larger worldwide I assume that it will have a stronger say in future polls than I&O, but right now it's being presented as a merger, and not a take-over. Also, I&O is still putting out polls independent of Ipsos. It's unclear whether this situation will continue. I hope it does — two polls is too little.

Verian

Verian seems to be the new name of Kantar, which bought TNS NIPO ages ago. So, though the name is new, the organisation is an old purveyor of political polls.

The Eén Vandaag TV programme switched to Varian from Ipsos I&O.

Historical overview

Some old election results because they're fun.

Calculations

I calculate my average and the coalitions as follows.

Polls

I treat the polls as follows:

1. I established weighting factors for the pollsters based on past performance. They are
2. I also use a decay factor based on the poll’s age. This is an exponential decay function with N₀ of 1, t in days, and λ of .
3. The polls are sorted according to the periods defined in the first table ( days).
4. For each period I take the polls of one pollster, multiply the individual party scores by the decay factor, and put them in a bucket by party.
5. I use the combined scores as votes in an election, which yields a average pollster score for this period.
6. Once I’ve done so for all pollsters I multiply the average pollster scores by the pollster weight and the decay factor of the most recent poll and put them in a bucket.
7. I again use the combined scores as votes in an election, which now yields my final average.
8. Election: this is an election according to the normal rules.
   In order to protect the small parties I use the system of highest remainders for rest seats, and I have no electoral threshold.

Coalitions

The script creates all possible coalitions and then rejects the following ones:

1. Coalitions with PvdA, CDA, and VVD.
2. Coalitions with fewer than seats.
3. Coalitions of which a subset already has seats.
4. Coalitions with parties that have excluded each other. (See sidebar for the current exclusion list.)
5. Coalitions with two or more parties that have fewer than seats.
6. Coalitions whose smallest party has fewer than seats, unless that party gives the coalition its majority in either parliament or senate.

The table shows the remaining coalitions.

Coalition likelihood

The likelihood of a coalition is calculated by the following formula that I tweaked by hand (there are few theoretical underpinnings here). I don’t doubt I’ll make frequent changes.

The formula is
1/SIZE * MAJORITY * SMALLEST * RELATION * SENATE

SIZE

the number of parties in the coalition

MAJORITY

the majority of the coalition (seats over 75)

SMALLEST

the size of the smallest party

RELATION

Each pair of parties has a relation from 0 (excluded) to 3 (preferred). The sidebar shows which parties have which relations.
The variable is the sum of the worst relations in the coalition.
(Coalitions in which any two parties have relation 0 are rejected automatically, so that value doesn’t occur.)

SENATE

Is 1 if the coalition has a majority in the senate, if it does not.

PVV

Is when a coalition contains CDA+PVV or VVD+PVV.
Otherwise it is 1.

Once the likelihood of all coalitions has been calculated, the results are treated as votes in an election for 100 seats. This yields the percentages that are shown in the table.