Polls

Here I study the polls.

My average

Here is my weighted average of the polls detailed below. It reports a shift of seats relative to current parliament.

See the party profiles for a description of the parties.

Method

I treat the polls as follows:

1. The current column uses the most recent poll of each pollster.
2. The short term column uses all polls that are at most days old, excluding the most recent ones.
3. The medium term column uses all polls that are between and days old.
4. The long term column uses the older polls.
5. I have established weighting factors for the pollsters based on past performance. They are
6. I also use a decay factor based on the poll’s age.
7. I assign bonus votes to some parties. See below.
8. I multiply the amount of seats of a party by both pollster weight and decay factor, and then add bonus votes. Then I add party scores from all polls and pollsters, and use the result as votes in 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.

Bonus votes

I assign bonus votes to some parties. They are supposed to represent the number of voters that right now say they won’t vote (and thus aren’t counted in the polls) but eventually will vote after all.

The best example is the PVV: some people don’t dare to own up to the fact they’re going to vote for it, and that’s why the PVV handily beat the polls in both 2006 and 2010. I want to add that effect to my calculations.

Still, bonus votes are rather speculative, and I’ll try to validate the percentages. Expect frequent changes here.

Coalitions

These tables are automatically generated — they 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 supports Rutte’s VVD+CDA government. The left-wing equivalent would be a PvdA+D66+GL government.

Still, 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 would have to have a majority, and it 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.

Calculating the coalitions

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

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

The table shows the remaining coalitions.

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

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.
Ideally, all party pairs in a coalition have relation 3. The variable is the sum of the actual relation scores divided by the sum of the ideal ones.

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.

Raw data

1. The most recent Politieke Barometer poll was released on ().
2. The most recent Peil.nl poll was released on ().
3. The most recent TNS-NIPO poll was released on ().

There are three pollsters in Dutch politics: the Politieke Barometer, Peil.nl, and TNS-NIPO. Here’s the raw JSON data; below are some nice tables.

Politieke Barometer

The Politieke Barometer publishes its poll every two weeks on Thursday.

I trust the Politieke Barometer more than the other two pollsters. Still, it may have a right-wing house effect.

Peil.nl

Peil.nl publishes its poll every week on Sunday.

Peil.nl is always out for sensational headlines. The swings are larger, the gloom and doom for former mass parties PvdA and CDA is deeper, and any sort of extremism is bigger. In addition, Peil.nl has a left-wing house effect.

TNS-NIPO

TNS-NIPO has started polling. So far they’ve released two polls with a month in between, but that month contained Christmas and New Year, so it could be they’re also aiming for once every two weeks.

SEO

(SEO bait for Dutch-language searches)

Hier vindt u de peilingen over de Tweede Kamer-verkiezingen en de Nederlandse politiek van Peil.nl (Maurice de Hond), Synovate / Politieke Barometer en TNS-NIPO. Tevens bevat deze pagina mijn gemiddelde van de peilingen en een berekening van de mogelijke coalities.