Quandary of Ranking Points

World Ranking Points are at stake in every match. The two teams World Ranking Points are compared with an artificial 3 added to the home team, then the two are plotted against each other on a graph with 5 possible results resulting in the change to the Ranking Points of the two teams.

Basically there are 3 lines on the graph with the difference between the modified ranking points along the X axis, and the change in ranking points after the game on the Y axis. With 0 on the X axis not at the intersection point of the Y axis.

The 5 results possible for the implication of Ranking Points are

Win by Home Team by Less than 15
Win by Home Team by More than 15
A Draw
Win by Away Team by Less than 15
Win by Away Team by More than 15

The 3 lines are higher ranked team wins, draw and lower ranked team wins. So lets take this weekend's game in Dublin.
Argentina are ranked 4th with 82.82 pts
Ireland are ranked 8th with 77.18 pts.

The difference in pts is 77.18 (Ireland's pts) - 82.82 (Argentina pts) + 3 (Home Advantage). So there is only a difference of 2.64. Meaning that there will not be a big difference in points depending on the result. But Ireland could still lose points if they lose the match, as reported on the BBC, they would lose 0.73 pts.
Now that is if they lose by less than 15 pts.

Because if a team wins by 15 or more points the core value is multiplied by 1.5, so Ireland would drop 1.095 pts not 0.73. I don't have the exact number of the gain if Ireland were to win, but it would be between 1 and 1.5 pts.

What is very interesting in the World Ranking Points and their implications on the World Cup groups is that if Ireland were to beat Argentina, then all the teams from 5th to 7th (England, France & Wales) have a chance to get into 4th.

Argentina are currently 4th and if they lose would lose around 1.25 pts
Argentina 4th on 82.82
England 5th 82.11
France 6th 80.13
Wales 7th 79.58

Simplest task is for England to beat South Africa. 3.34 modified difference in pts, a lot of chance to gain pts, around +1.25, putting them 4th regardless of other events, depending on their next game against New Zealand.
Now if Argentina win (and by more than 15 pts as well), England could still overtake them by winning by over 15 pts. England would overtake Argentina by around 0.2 rating pts. Because England would gain more from beating South Africa than Argentina gain by beating Ireland, especially when multiplied by 1.5 for the big win.

For Wales to get 4th place they would need to beat New Zealand and Argentina, England & France to lose. A Modified difference of 9.83 would see them pick up 2 full pts with a win, but still need the others to lose pts not gain any.

France play Australia and would need to win by more than 15 pts to get into 4th place. The modified difference between the two teams is 3.57 which would see them gain around 1.36 pts or 2 if they win by 15 in the game. So under Argentina and England's current ranking, so require both to lose for their their new 82+ ranking to be enough to be 4th. They would also require Wales to not beat New Zealand by 15 pts or else that would put them ahead of France.

Lower down the World Ranking System, there is a direct match up for the last place in the 2nd pot of teams. Ireland need a win to stay 8th (unlikely to gain 7th, require 15+ win and Wales to lose by 15+) but it is being above 9th that matters not how high unless it is top 4.

Ireland play Canada, New Zealand & Argentina in the Autumn Internationals.
Scotland play New Zealand, South Africa & Canada.

Ireland beat Canada by more than 15 pts, Lost to New Zealand by 15 pts.
If Ireland fail to beat Argentina they would drop to 9th place.
Scotland lost to New Zealand by more than 15pts, lost to South Africa by less than 15 pts and are likely to beat Canada by more than 15 pts moving them to 8th place.

So what I find odd is that since they have similar results Ireland would lose the place.

So it is an interesting weekend of rugby ahead to determine what pot the teams are in when the draw for RWC 2011 is made on December 1st. It is about time that World Rankings are being considered not just previous world cup performance. Of course, it is still being used somewhat, as there are 12 teams that will be in the 3 seeded pots not the top 12 in the World.