Jurors and Media

Meaning of the jury

It has been sworn in to take over the performance of their duties or occupation. Interpreter, vocal, supplier jury.

Institution for the participation of citizens in the administration of justice, by which persons designated by lot contribute to the prosecution of certain crimes, through the issuance of a verdict on the evidence of the facts. Each of the persons who compose the court. Collective body that selects the most qualified of candidates for an award, honor, distinction, or employment. Each member of that body. Man in charge concerned the provision of food in town halls and councils.

In its classical formulation, the Condorcet Jury Theorem concerns collective judgment by majority voting. For example, a jury might have to decide whether it thinks that Jack is guilty or innocent of killing Jill. Every member of the voting body, in this case the jury, votes between two alternatives, of which only one is correct. The collective chooses the alternative that receives most votes. In the example, each juror votes for guilt or innocence, and the verdict that receives most votes is chosen. It is assumed that consulting a single voter gives a better chance of a correct result than flipping a fair coin: the chance that a juror correctly chooses between guilt and innocence is larger than a half. The Condorcet Jury Theorem then states that if we include ever more voters in the collective, then the chance that the collective chooses the correct alternative tends to one. Put simply, the Condorcet Jury Theorem reflects the wisdom of the crowd. The classical formulation of the theorem concerns the chances of a correct decision only. In the example, it concerns the chance of a majority vote for guilt if in actual fact Jack is guilty. (Vallone, Ross, 585)

As such, it does not say anything about the probability of the alternatives being true or false after all the votes have been tallied. However, under fairly general conditions we can deduce that with increasing size of the voting body, the probability associated with the true alternative tends to one as well. We can even derive a simple formula for the probability of the two alternatives, the so-called Condorcet formula. If we assume that the alternatives are of equal probability before voting has taken place and if we further assume that the chance that a voter chooses correctly is independent of which alternative happens to be true (often referred to as the symmetry of the juror competence), then the probability of the alternatives is a function only of the absolute margin between the voters for each of the alternatives: the larger the numerical difference between those who voted for Jack's guilt against those who voted for his innocence, the stronger the support for Jack's guilt.

The size of the jury does not come into this equation. Despite possible appearances to the contrary, the fact that the support according to the Condorcet formula is independent of the jury size is in keeping with ...