The Eurovision Tune Contest used to be based 70 years in the past as some way for Europe, divided after conflict, to return in combination by way of celebrating its tune. Annually, a number of dozen international locations around the continent – and, extra just lately, a long way past – compete in what is thought of as the sector’s maximum seen non-sporting match.
As a cultural establishment that final yr attracted round 166 million audience, the result of Eurovision have a large have an effect on – now not least by way of deciding the venue of the next yr’s match. But the problem of bloc vote casting, the place international locations have a tendency to vote extra favourably inside regional or cultural blocs, has lengthy been a debatable facet of the competition.
In 2008, the BBC’s Eurovision commentator Terry Wogan spoke out towards bloc vote casting by way of Japanese Ecu international locations, announcing: “You have to say that this is no longer a music contest. I have to decide whether I want to do this again.” He didn’t – it used to be his last display within the statement hotseat.
Infrequently, suspiciously pleasant vote casting has strayed into one thing much more troubling. The 1968 contest, held on the Royal Albert Corridor in London, noticed a significant dissatisfied when house favorite Congratulations, sung by way of Cliff Richard, used to be pipped by way of the Spanish access L. a., L. a., L. a..
40 years later, Spanish Eurovision host Jose Maria Inigo claimed that the vote have been rigged on the behest of Spain’s army dictator, Franco. His claims had been later supported by way of an Irish TV investigation.
The fashionable, expanded Eurovision options two semi-finals in addition to the grand last, held this yr in Vienna on Might 16. Its scoring combines a jury panel with a public vote, decreasing the have an effect on of every jury. However that didn’t prevent any other main vote casting scandal rising in 2022.
The 2022 scandal
Throughout the 2022 grand last in Turin, Italy, the Ecu Broadcasting Union (EBU) introduced that six juries’ rankings from the second one semi-final – Azerbaijan, Georgia, Montenegro, Poland, Romania and San Marino – have been nullified after “certain irregular voting patterns were identified in the results of [these] countries”.
The international locations’ votes had been changed with an mixture rating “based on the results of other countries with similar voting records” for each the semi-final and grand last. This procedure used to be said by way of Eurovision’s Impartial Balloting Track.
The international locations’ broadcasters strongly denied any wrongdoing, with Georgia even suggesting their first-place vote within the last have been wrongly allotted because of the imposed device. Amongst on-line audiences, there used to be speedy hypothesis of a cover-up. After the overall, the EBU issued an extended rationalization for his or her choice.
So had there in point of fact been collusion? Colleagues and I from the College of Stirling, together with Riley Uttley, have re-assessed the 2022 vote casting scandal the usage of carried out statistical strategies.
Every five-member Eurovision jury decided on their ten favorite songs, with 12 issues going to their favorite, ten issues for 2nd, then 8 down to at least one for his or her tenth-best tune. A identical issues device used to be used to replicate every nation’s public vote, doubling the entire selection of votes awarded by way of every nation.
The jury effects previous to the EBU’s intervention are proven under. The six juries whose rankings had been nullified – marked in pink – awarded every different a complete of 251 issues. That is simply seven issues shy of absolutely the most they may have given every different: 6 x (12+10+8+7+6) = 258 issues.
Eurovision jury rankings, 2022 2nd semi-final
Rankings in pink had been later nullified. Issues come with 3 non-competing juries: Germany, Spain and UK.
Robin Hankin, CC BY
If the rankings had been allotted randomly, the percentages of the six international locations awarding every different 251 issues could be lower than 1 in 10,000. One of these low chance supplies sturdy goal proof that the six juries had been certainly colluding.
However carried out statistics can exactly quantify the power of this collusion – the usage of a model of the Bradley-Terry (BT) way of paired comparisons, first printed in December 1952.
Calculating the power of collusion
Say we’ve got two songs, a and b, and need to know the chance {that a} is judged higher than b. The usage of the BT way, this chance is:
p(a) / p(a) + p(b)
the place p(a) and p(b) are the respective strengths of the 2 songs.
This concept will also be prolonged to the rating of any selection of songs. If we practice, say, {that a} ≻ b ≻ c ≻ d ≻ e (this is, tune a is the most productive, then b, all the way down to e), the chance of this vote casting choice is:

That is referred to as a Plackett-Luce probability serve as. Whilst calculating every worth is hard, we will be able to use same old optimisation ways to maximize this chance, and thereby estimate the strengths of the songs.
In relation to figuring out the power of collusion within the 2022 contest, my very own method referred to as reified Bradley-Terry will also be carried out to this probability serve as.
The unfair benefit of collusion is represented by way of including an additional power time period to any competitor who benefitted from collusion. Within the equation under, S represents the power of the collusion impact, and is carried out to tune b. So, we substitute each incidence of p(b) with p(b)+S. Then, the chance of a ≻ b ≻ c ≻ d ≻ e is now:

The Eurovision 2022 semifinal had 18 songs and 21 juries, resulting in a chance equation like the only above – however with a complete of 220 phrases. Whilst this can be a lot for an individual to paintings with, it may be simply treated by way of the R programming language, an open-source statistical instrument designed to take care of plenty of knowledge and bring graphics and visualisations.
The got rid of juries all perceived to have very identical behaviour, so we represented the power of the collusion of all six as a unmarried quantity S, which we calculated to be 0.262. We then calculated the chance of S being as top, or upper, than this worth at the assumption of no collusion.
We calculated this chance to be one in 58,000. Put differently, when you have 2.5km of matchsticks laid out end-to-end and burn one, it’s the chance of choosing the burnt one. We will be able to, subsequently, hopefully conclude that collusion did happen.
The 2026 vote casting device defined. Video: Eurovision Tune Contest.
A last quirk
The 2022 Eurovision vote casting scandal had ramifications past the nullification of the six collusive rankings. Jury vote casting for semi-finals used to be discontinued from 2023 till this yr’s contest. Most likely perversely, this made the juries raise extra weight in every grand last.
With the semi-finals made up our minds purely by way of public votes, which have a tendency to be extra dispersed and unpredictable, this supposed the juries’ extra concentrated vote casting patterns performed a extra vital function in deciding without equal winner.
Jury vote casting used to be reinstated for the semi-finals of this yr’s contest. Alternatively, the juries are higher (seven contributors somewhat than 5) and selected from a extra various background.
The transparent favourites, Finland, will hope that is any other step against removing the debatable vote casting patterns that experience haunted previous contests – and made Eurovision a focal point of prepared passion for some carried out statisticians.