IRB World Rankings
IRB World Rankings
|Top 25 Rankings as of 15 April 2013|
|*Change from the previous week|
The IRB World Rankings is a ranking system for men's national teams in rugby union, managed by the International Rugby Board (IRB), the sport's governing body. The teams of the IRB's member nations are ranked based on their game results, with the most successful teams being ranked highest. A point system is used, with points being awarded based on the results of IRB-recognized international matches. Rankings are based on a team's performance, with more recent results and more significant matches being more heavily weighted to help reflect the current competitive state of a team. The ranking system was introduced the month before the 2003 Rugby World Cup, with the first new rankings issued on 8 September 2003.
Uses of the rankings 
The rankings are used by the IRB to rank the progression and current ability of the national rugby union teams of its member nations, but the data was historically used by the IRB for very few things. Until 2007 the rankings were not used to seed competitions such as the Rugby World Cup, the IRB using results from previous World Cups.
Rank leaders 
When the system was introduced England were the top team and maintained that position following victory in the 2003 Rugby World Cup. New Zealand took the lead from 7 June 2004. After winning the 2007 Rugby World Cup final, South Africa became the third team to achieve first place. The first two fixtures of the 2008 Tri Nations resulted in the top two teams switching places: the All Blacks regained the top spot after defeating South Africa in the Tri Nations opener on 5 July 2008 in Wellington; a week later the Springboks returned the favour in Dunedin, scoring their first win over the All Blacks in New Zealand since 1998, reclaiming the top spot, only for the All Blacks to defeat both Australia and South Africa in August 2008 to regain the top spot by a considerable margin. South Africa regained the lead in July 2009 after beating New Zealand in Bloemfontein and kept the lead until losing to France in November of that year, allowing the All Blacks to regain the top spot.
New Zealand have been the most consistently ranked #1 team since the introduction of IRB World Rankings having held the #1 ranking for nearly three-quarters of the time during this period. South Africa and England make up the remainder.
Best and worst 
Current calculation method 
All IRB member countries have been given a rating that is in the range of 0 to 100 with the top side achieving a rating of about 90 points. The point system is calculated using a 'Points Exchange' system, in which sides receive points from each other based upon the match result – whatever one side gains, the other loses. The exchanges are based on the match result, the ranking of each team, and the margin of victory, with an allowance for home advantage. As the system aims to depict current team strengths, past successes or losses will fade and be superseded by more recent results. Thus, it is thought that it will produce an accurate picture depicting the actual current strength and thus rank of the nations. The rankings are responsive to results and it is possible to climb to the top from the bottom (and vice-versa) in less than 20 matches. As all matches are worth a total of 0 points there is no particular advantage to playing more matches. A rating stays the same until the team plays again. Although matches often result in points exchanges, 'predictable' results lead to very minor changes, and may result in no change to either side's rating.
The system ensures that it is representative of the teams' performance despite playing differing numbers of matches per annum, and the differing strength of opposition that teams have to face. The factors taken into account are as follows:
- Match result
- Match status
- Opposition strength
- Home advantage
Match result 
For each match played points exchanges are awarded for the following five outcomes and was developed using results of international matches from 1871 to the present day:
- a win or loss by more than 15 points
- a win or loss by up to 15 points
- a draw
Match status 
Different matches have different importance to teams, and the IRB has tried to respect this by using a weighting system, where the most significant matches are in the World Cup Finals. Points exchanges are doubled during the World Cup Finals to recognise the unique importance of this event. 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. Matches that do not have full international status do not count.
Opposition strength 
A win against a very highly ranked opponent is a considerably greater achievement than a win against a low-rated opponent, so the strength of the opposing team is a factor. Thus match results are more important than margins of victory in producing accurate rankings. This is because when a highly ranked tier 1 team plays a lowly ranked tier 3 team and manages to beat them by over 50 points, it does not necessarily indicate how either team will perform in the future.
Home advantage 
When calculating points exchanges, the home side is handicapped by treating them as though they are three rating points better than their current rating. This results in the home side gaining fewer points for winning and losing more points for losing. Because of this, any advantage that a side may have by playing in front of their home crowd is cancelled out.
New and dormant nations 
All new member nations start with 30.00 points, which is provisional until they have completed ten test matches. When countries merge, the new country inherits the higher rating of the two countries but when they split (e.g., the planned 2010 breakup of the Arabian Gulf rugby union team into separate teams representing its current member countries), the new countries will inherit a rating at a fixed level below the rating of the original country.
Before 1 December, 2012 new member nations were given 40.00 points.
Countries that have not played a test for a couple of years are removed from the ranking system and the list. If they become active again, they resume their previous rating.