The Odds Lab

The maths of treachery

Three small experiments behind the Burn Vote meter. Drag the sliders, flip the switches, and find out how much a single twitchy breakfast is really worth.

Experiment 1

Bayes at breakfast

Start with how likely a guest is to be a Traitor before you know anything about them. Then add clues. Each clue multiplies the odds by its likelihood ratio: how much more often Traitors produce it than Faithfuls.

27%
Clues you saw
27%

chance this guest is a Traitor

Experiment 2

10,000 round tables

A stripped-down castle: every round table banishes the most-voted guest, every night the Traitors murder a Faithful. Each Faithful has a chance of voting for a real Traitor; otherwise they vote at random. How good do they need to be?

12
3
20%
—

Faithful win rate

How long the games lasted

Faithful win rate by accuracy

Show the numbers as a table
Experiment 3

The wisdom of the table

Two suspects, one is the Traitor. Each guest independently picks the right one with probability p. In 1785 the Marquis de Condorcet showed that if p is above 50%, a bigger table makes the majority more and more likely to be right — and if it's below 50%, a bigger table makes it worse.

60%
11
—

chance the majority picks the Traitor

The catch, in real castles: votes aren't independent. Guests talk, herd, and get herded — sometimes by the Traitors themselves.