Discussion:Classement World Rugby des équipes nationales de rugby à XV

Utilité de la page

Cette page est-elle utile en l'état ? Il serait plus intéressant de parler de la date à laquelle ce classement a été créé, de son évolution. Mais le classement évoluant toute les semaines, ne serait-il pas plus judicieux de renvoyer au site officiel plutôt que le recopier ? -- elg - contact 11 septembre 2007 à 12:05 (CEST)

Calcul

Sur quelles bases le calcul est fait? Skiff 17 septembre 2007 à 19:52 (CEST)

as we are all fluent in english:

The IRB World Rankings are calculated using a 'Points Exchange' system, in which sides take points off each other based on the match result. Whatever one side gains, the other loses.

The exchanges are based on the match result, the relative strength of each team, and the margin of victory, and there is an allowance for home advantage.

Points exchanges are doubled during the World Cup Finals to recognise the unique importance of this event, but all other full international matches are treated the same, to be as fair as possible to countries playing a different mix of friendly and competitive matches across the world.

Any match that is not a full international between two member countries does not count at all.

All member countries have a rating, typically between 0 and 100. The top side in the world will normally have a rating above 90.

For illustration, we'll use the Six Nations match between Wales and Scotland in Cardiff on 14 February 2004, to describe the process.

Step One: Check pre match ratings

The top 10 countries in the IRB World Rankings, immediately before the match, are shown below. Wales were on a rating of 76.92 and Scotland slightly lower on 76.36.

Step Two: Allow for home advantage

To 'handicap' the home side, we treat them as though they are three points stronger than their current rating, which means that they will tend to pick up fewer points for winning, and give away more points for losing

This gives Wales a rating of 76.92 +3 = 79.92, against Scotland's rating of 76.36.

Step Three: Calculate the Rating Gap

The Rating Gap is the difference between the ratings of the two sides

Allowing for home advantage it is 79.92 - 76.36 = 3.56 (in favour of Wales).

Step Four: Check the possible Core Rating Changes

Core Rating Changes are based on the match result and the Rating Gap

As illustrated in the diagram below, with a Rating Gap of 3.56, if Wales won their Core Rating Change would be up, and Scotland's down, by 0.64

Again as illustrated below, if the game was drawn, Wales Core Rating Change would be down, and Scotland's up, by 0.36

And finally if Scotland won their Core Rating Change would be up, and Wales's down, by 1.36.

So Wales, as the higher rated side (especially allowing for home advantage) would pick up fewer points than Scotland if they won the match, and would give away more points if they lost.

Step Five: Apply weighting factors

If one side has won by more than 15 points, we multiply the Core Rating Change by 1.5. So if Wales won 30-10 the points exchange would be 0.64 x 1.5 = 0.96.

If the match was part of the World Cup Finals, we would then double the Rating Change.

What happened?

Wales won the match 23-10, so the sides exchanged 0.64 rating points, with Wales going up to 77.57 and Scotland going down to 75.72.

Dingy 17 septembre 2007 à 20:18 (CEST)

Formule de calcul

L'IRB ne fournit pas tous les détails de sa formule. Celle-ci a donc été reconstituée (et vérifée par mes soins) d'après les récents résultats. Si quelqu'un veut confirmer... -- Prokofiev - contact 15 octobre 2007 à 14:16 (CEST)

Je confirme : tes formules sont fausses, il suffit de regarder les diagrammes de l'IRB (http://www.irb.com/rankings/explain/index.html), ce ne sont pas des droites (encore heureux...) 82.227.205.8 (d) 21 novembre 2009 à 20:27 (CET)

je confirme elle sont juste c'est du linéaire avec limite min et max (encore heureux...)c'est bien la différence divisée par 10 rien de compliqué. par contre quid de la coupe du monde et du pays hote pour le +3 et des equipe dite a domicile pour le jeux de maillot. (les seul ecart consatés en utilisant ta formule peuvent venir des arrondi c'est tous).

rapide remonter des archive est: tous les matchs de RWC sont considérés comme etant sur terrain neutre sauf si le pays hote joue dans sont pays. la france bat la NZ en 2007 au pays de gales terain neutre... la france perds contre l'angleterre la semaine d'aprés au stade de france considéré comme a domicile donc +3 au classement et du coup grosse chute. 9a vas etre dur pour les NZ de marquer des points chez eux a la prochaine coupe du monde.... --194.214.128.231 (d) 4 mars 2010 à 12:23 (CET)