Data Science: Block voting in The Eurovision Song Contest

The Eurovision Song Contest started out as a technological experiment for live tv broadcast across Europe in 1956, but has grown to become an institution, a mass spectacle of kitsch and glam with hundreds of millions of viewers across the globe. But there is one thing that is consistently blamed for ruining the competition: block voting. But exactly what are the blocks, and how big influence do they have? Let’s try and find out!

Overview of recent competitions

Before identifying any blocks, we’ll have a look at past winners to get a sense for what is going on. Below are maps showing, for the years 2001–2018, which countries the points for the winner and runner-up came from. Although block voting is clearly happening in some cases (Serbia’s win in 2007 and Azerbaijan’s win in 2011 stand out in particular), winners tend to receive points from all over Europe, and a block is rarely able to swing the competition without supporting votes from countries outside the block.

Previous Year (Left), Next Year (Right)

One reason why a block usually can’t determine the winner is that while they vote for each other to a higher degree, they don’t necessarily agree on one best act who scores highly from all members of the block.
Sometimes, although this doesn’t happen very frequently, a block does ‘works together’ and all vote for the same country, and with support from outside the block they can decide the winner. This happened most clearly in 2007, when all former Yugoslavian countries gave Serbia 12 points. However, Serbia wouldn’t have won without also getting consistently high scores from mainly central and northern Europe.

So which blocks are there?

While some patterns are easy to spot (Moldova and Romania almost always exchange 12 points, as do Greece and Cyprus), bigger groups can be harder to identify. Since not all countries participate in all stages (the two semifinals and the final), the data is sparse which further complicates analysis.
To tackle this, we fit a statistical model that untangles the inherent preferences that exist between countries from the overall popularity of a song. This lets us combine results from different stages (and years) in a consistent way. As the voting system has changed quite a few times over the years, we limited ourselves to the time period between 2010–2015 when the votes were determined by a combination of televotes and jury. This lets us:

  • analyse the biases countries show for each other and identify blocks, and
  • eliminate these biases to find the ‘true’ rankings each year.

We’ll explain exactly how this model works in a future post, but for now let’s have a look at the results. Once we have extracted the biases, we can use cluster analysis to help us identify the blocks (we use a method based on information theoretic co-clustering). Doing this, we find three blocks: a tightly knit block with the ex-Yugoslavian countries including Albania; an eastern block, centred around Ukraine, Georgia and Azerbaijan; and a western block centred around the Nordic countries. This is in line with previous analyses. The blocks are shown on the map below, where a darker shade indicates a stronger association with the block.

Another way to visualise this is to look at the individual biases, shown in the graph below. Here we can clearly see the strong connections within the ex-Yugoslav block, as well as parts of the eastern block. However, the western block is much less tightly knit.
The close relationships between Romania and Moldova, and Greece and Cyprus also stand out.

Did the best song win?

In the process of building the model, we also get the unbiased ‘quality’ of each entry. So how do these compare to the final results? In fact we found that the ‘best’ song won in all of the years we covered. However there are some changes further down the ranks, where our model favours a third place act over a runner-up, especially when the vote is close. This is consistent with our assertion earlier that to win you need broad support, just getting votes from your block is not enough.


We have found that, although block voting happens to a high degree, it doesn’t in general determine who ultimately wins the competition. To win you need broad support, and to do that you need to put on a good show. Which doesn’t necessarily mean a good song…