Learn

Elections look simple from the outside: people vote, someone wins. Underneath, every country turns votes into seats its own way. These are the ideas you'll meet across ATLAS, in plain words.

From votes to seats

The same votes can give very different parliaments, depending on the rules.

Proportional representation

Parties get seats roughly in proportion to their votes. Most of Europe works this way, usually with the country split into districts that each elect several members (Portugal, Spain, Poland), or as one nationwide list (the Netherlands).

First past the post

Each district elects one member: whoever gets the most votes wins it, even without a majority. Big parties gain, small parties spread across the country often win nothing. The United Kingdom uses it.

Two rounds

If nobody wins a majority in the first round, the leading candidates meet in a second. France elects its National Assembly like this, district by district.

Mixed systems

Some members are elected in single districts, others from party lists. In Germany the lists balance the result so seats match the party vote; in Lithuania and Italy the two parts are counted separately.

Dividing the seats

Inside a proportional system, a formula decides who gets the last seats in each district.

D'Hondt

Divides each party's votes by 1, 2, 3… and hands out seats to the biggest results. It slightly favours larger parties, more so in small districts. Used in Portugal, Spain, Poland and the Netherlands.

Sainte-Laguë

Divides by 1, 3, 5… instead, which treats medium and small parties a little better. Germany's Bundestag and Sweden use versions of it.

Thresholds

Many countries only give seats to parties above a minimum share: 5% nationally in Germany and Poland, 3% per district in Spain. Votes for parties below it don't turn into seats.

District size

A district with 2 seats is far harder to win than one with 40: a party needs a much bigger share there. That's why the same national result can give different seats in different countries.

Majorities and coalitions

A majority is half of the seats plus one: 116 of 230 in Portugal, 76 of 150 in the Netherlands. When no party reaches it alone, parties can form a coalition government together, or one party can govern as a minority, relying on others to pass laws case by case.

In the parliament diagrams on ATLAS, seats are drawn from left to right, roughly as parties sit, and the small mark at the top shows where a majority is crossed.

Polls, averages and projections

A poll

A survey of usually 800 to 3,000 people. With 1,000 people, a party's real share is typically within about 3 points of the poll's number, either way. One poll alone can easily be off.

A polling average

Combines many polls, giving more weight to recent ones, bigger samples and pollsters with a good record. It's steadier than any single poll, and less likely to chase noise.

House effects

Pollsters ask questions differently, so some lean a little towards certain parties, poll after poll. Averages soften this by mixing many companies.

Projection, not prediction

ATLAS's projection shows the seats parties would win if the election were held today, with the average's shares. It's a snapshot of the present, not a forecast of election day.