Teams will need luck on their side if they are to be successful

SCORES at Euro 2020 in all likelihood will be determined partly by skill and partly by luck. Why do I say this? Let me start my answer by asking you a question.

How often in a group at a European Championship will team A beat team B who then beat team C who then beat team A?

If there were differences in skill between all teams, and results were determined only by skill, it would never happen. If there were no differences in skill between teams, and results were therefore decided entirely by luck, it should happen five per cent of the time. I will explain why in a moment.

How often has it happened during the group stages of a European Championship? Three per cent of the time – that is to say, in three per cent of all sequences in which a first team played a second team who then played a third team who then played the first team.

I studied every European Championship group phase – from 1980 up to 2016. Twenty-six per cent of games were drawn. If there were no differences in skill between teams then in each game there would have been a 26 per cent chance of a draw, a 37 per cent chance of a win for this team and a 37 per cent chance of a win for that team. The chance of team A beating team B, then team B beating team C, then team C beating team A, would have been 37 per cent x 37 per cent x 37 per cent, which is five per cent.

In any sport if two competitors have the same skill then the result of a contest between them cannot be decided by a difference in skill – there is none. It must be decided instead by luck.

At a European Championship sometimes there can be other influences on the third round of group games. If team A won their first two games they might have qualified already and field reserves against team C, who might still be able to qualify themselves if they can get something from this game.

Even after allowing for such situations, however, there are still many others in which results suggest that international football at tournaments is at least as much like a game of pure luck as a game of pure skill – as much like roulette as chess.