#广场预测世界杯赢40000U Why are there more and more upsets in the World Cup? Math has long told you...

There's a line in *Goal! The Dream Begins*: In the world of football, the impossible happens every day.
You might think this is inspirational. But it's actually math.

First, let's talk about a number that stunned everyone.
At the 2018 World Cup, Germany lost 0-2 to South Korea in the group stage and finished last in their group. The world was shocked. But at the time, the odds from BC company were 1:17. Converted to probability: South Korea winning had only a 5.6% chance.
Theoretically, such an event happens once every 18 matches. But there were only 48 group-stage matches in that World Cup—and it just happened to occur.
Some say: luck. Some say: complacency. Mathematicians say: This isn't an accident; it's the Poisson distribution.

Second, what is the Poisson distribution? In simple terms.
A football match lasts 90 minutes, with few goals scored. The average number of goals per match is around 2 to 3. This kind of "rare random event within a unit of time" can be precisely modeled using the Poisson distribution.
The formula looks scary, but the principle is simple:
If a team averages 2 goals per match (λ=2), then:
Probability of scoring 0 goals: 13.5%
Probability of scoring 1 goal: 27.1%
Probability of scoring 2 goals: 27.1%
Probability of scoring 3 goals: 18.0%
Probability of scoring 4 or more: about 14.3%
A weak team scoring 3 goals in an upset? Mathematically, it's possible, just with low probability. Low probability does not mean it won't happen.

Third, why will there be more upsets in 2026?
2018 World Cup: 32 teams, 48 group-stage matches. 2026 World Cup: 48 teams, 72 group-stage matches. That's a full **50%** increase in matches. Every additional match is another "launch opportunity" for a low-probability event.
We did a rough estimate: Assume that in each match, the probability of a major upset (strong team being beaten) is about 5%.
With 48 matches: Expected about 2.4 major upsets.
With 72 matches: Expected about 3.6 major upsets.
That's a full 50% increase.
In other words: You're not just seeing more upsets—there are simply more upsets. This isn't a feeling; it's math speaking.

Fourth, so is AI prediction useful? That's the core question.
Since football is so random, what's the point of predictions? The answer is: partially useful, but you need to understand the boundaries of "usefulness."

Fifth, backtesting data speaks.
We conducted offline validation on 192 matches from the 2014, 2018, and 2022 World Cups. The conclusion is clear:
In group stages, where strength differences are obvious, the model has reference value.
In knockout stages, where it's one match to decide, randomness surges, and the model significantly weakens.
High-confidence matches are the most worth referencing—but each World Cup has only about 20 such matches.
The essence of upsets is the normal occurrence of low-probability events.
It's not a bug, not match-fixing, not luck. It's the Poisson distribution saying: You planned for every possibility, but football keeps that 5% just to make the world remember it.

Sixth, for 2026, which matches should you pay most attention to?
Our suggestion:
Third round of group stage: With tight standings, some strong teams already qualified, reduced motivation for starters, high upset probability.
Asia/Africa vs. Europe: Biggest ELO gap, but the Poisson distribution tells you: the larger the gap, the stronger the "shock value" when an upset occasionally happens.
Matches with confidence ≥ 60%: System-specific marking, historically the most worth paying attention to.