Lesson 01 · 3 min · 5 things to do
Winning is not the same as being better
Estimate how often the weaker side wins a single match.
The best team in a league plays the worst. How often does the worst team win?
- Yes.In most team sports the stronger side wins somewhere between half and three quarters of the time. A single result is one draw from that, not a measurement of who is better.
- Not quite.Upsets happen constantly, which is most of why people watch. If the better side always won there would be no fixture.
- Not quite.The weaker team wins plenty of matches in which the stronger side played well. One goal decides too much.
A match result is a sample. It contains the difference in quality plus everything else that happened that afternoon.
One team is genuinely better. Slide the size of the gap and see how often it actually wins.
SlightlyClearlyEnormously11 of 20 · wins for the better team, out of 20
SlightlyIt wins about 55% of the time. Two matches in five go the other way.
13 of 20 · wins for the better team, out of 20
ClearlyAbout 65%. A seven-match losing run is still perfectly possible.
17 of 20 · wins for the better team, out of 20
EnormouslyAbout 85% — and the underdog still wins three times in twenty.
Even an enormous gap leaves upsets. What does that make a knockout cup?
- Yes.One match is a coin weighted toward the better side. Seven rounds of a weighted coin produce a worthy winner far more often than the true best — which is a feature, not a flaw, if you want drama.
- Not quite.It is a fair procedure. Fairness of procedure and accuracy of result are different things.
- Not quite.The better side really is favoured every round. Favoured is a long way from certain.
Move the control to see what changes.
A team wins each match with probability 0.65. What is the chance it wins three in a row, as a percentage?
%Yes.0.65 cubed. A clearly better team fails to win three in a row nearly three times out of four — which is how a good side gets called a crisis club in October.Which of these are mostly skill, and which mostly the luck of one afternoon?
A club's league position after 38 games.
Winning a penalty shootout.
Shots created per match, over a season.
A deflected winner in the 89th minute.
A team's record across three seasons.
Yes.The pattern is the same everywhere: skill shows up in totals over many events, and single moments are dominated by everything else. That is why coaches talk about performances and supporters talk about results.A manager is sacked after four defeats. What is the problem with that decision?
- Yes.The arithmetic above says a genuinely good team loses four in a row reasonably often. The sacking usually looks vindicated afterwards, because whatever happens next is compared against the worst moment.
- Not quite.Results are the goal. Four of them are not enough evidence to attribute anything.
- Not quite.They do, and measurably. The point is how many matches it takes to see it.
Lesson complete
One match is a weighted coin, not a measurement of who is better.
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