The previews were first introduced in the first edition and each showed several of the songs participating in the edition. The countries are allocated to their preview based on when they revealed their entry.
Most of the broadcasters open a poll and let people vote for their favourites from each preview. The rankings of the countries in the previews by each broadcaster are used for the betting odds with the average place of each country representing their chances to win the contest.
The betting odds were also first introduced in the first edition. The rankings of each broadcaster in the previews were combined and the average score of each country represented their odds to win the contest.
Since their introduction in the first edition, the betting odds have predicted the first winner right, Finland in the first edition. Most of the betting odds' top 10–15 had similar result in the contest. However, there were several occasions where the favourites of the betting odds did not manage to do well, such as Luxembourg and the United Kingdom in the first edition, where the countries placed fourteen and ten places lower than predicted, or where the lower ranked countries of the edition did better than expected, such as Sweden in the first edition who finished fourteen places higher than in the betting odds.
The entry with the best odds was the Finnish entry in the first edition, "Elefantin Paino by Ellinoora. The entry with the worst odds was the Portuguese entry in the first edition, "Meu Amor de Longe" performed by Raquel Tavares.
A list with the best averages in the betting odds.
A list with the worst averages in the betting odds.
This table shows the odds and ranks the eventual winners of the contest had at the time.