FIFA Women's World Ranking Methodology
General Considerations
In the FIFA Women’s World Ranking teams are ranked according to a value that is a measure of their actual strength. A considerable amount can therefore be learned about the ranking value (or rating points) of a team. For example if a team meets their opponents in a knock-out match on neutral ground it has 72 rating points more, their chances of going through to the next round, are 60%.
FIFA Women's World Ranking - Why?
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Promotion of the Women's Game
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Realistic Assessment: Putting Everyone in their Place
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Statistical Analysis of the state of the Women's Game
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Equal Importance of Women's and Men's Football
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Solid foundation: some 3000 games since 1971
Although a certain amount of mathematics is inevitable, the system used is still easily understandable and enables all interested parties to understand the teams' movements, or even to calculate the Ranking themselves. Since the first match dates back to a little over 30 years ago (the first women's international was held on 17 April 1971 when France faced the Netherlands), it has been possible to comprehensively catalogue the data about international women's football.
FIFA Women's World Ranking - Key Criteria
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Result of the Match
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Home vs away, or neutral ground
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Importance of the match
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Difference in WWR between the teams
Basics of the Ranking method
The basic formula of the WWR is in fact quite simple:
WWR,new = WWR,old + ( Actual - Predicted )
The result of a team's match is converted into a value: "Actual". Via some formulae, the difference in rating points (strength) results in a "Predicted" value.
Should the "Actual" value be better, then the new WWR will be higher than the old one. This is fair, as the team will have delivered more than was expected. The underachiever loses the same amount of rating points as their opponents have won; their "Predicted" result is greater than their "Actual" result, i.e. they have not done as well as expected.
One conclusion that can be drawn from this basic rule is that the rating points earned by a team for a win is dependent on the strength of the opponent. A win over an extremely weak team scarcely improves their standing in the WWR, while a win over a stronger team is awarded with a clear increase of the WWR value.
Actual Result of the Match
Winning or losing of course is the most important criteria, but goal difference and goals scored are also taken into account as is shown in the following table.
Neutral ground or Home vs. Away
To correct the value for a home advantage, the rating points of the Home team are enhanced by a value "H". A glance at the historical results shows that teams perform better at home than away; the home teams keep 66% of the points, while the opponents return home with 34%. To neutralise this effect, a correction is made by enhancing the rating of the home team by a value of 100 points (corresponding to 64%).
Importance of the match
In friendly matches, the teams representing their countries are not necessarily the best a country has to offer, whilst it is clear that in the FIFA Women’s World Cup Final two “ultimate” teams will appear. As a result, matches held at important (qualification) tournaments are a more precise measure of the strength of a team than a friendly. This element is taken into account by introducing the Match Importance “M” factor.
For matches during the FIFA Women’s World Cup final tournament, this factor is four times bigger than the value of friendly matches, and for World Cup qualifying matches the difference is a factor of three. So, at major competitions, a lot more rating points can be earned and lost.
However, for friendly matches amongst the top 10 ranked teams, the prestige of these matches make them of more importance and hence also a better estimate of the strength of the teams involved. Therefore, the friendly matches amongst the top 10 ranked teams are awarded double importance compared to regular friendlies.
Difference in Rating Points
The scaled difference in rating points between the two opponents “x” (x = [r1 - r2] / scaling factor) is used to predict the result of the match. The formula used to do so is of the form: P (x) = 1 / [1 + 10 ( x / 2 ) ]
For each team the prediction match percentage “P” is expressed in a value between 0 and 1 as a function of the difference in scaled rating points “x”.
The scaling factor is chosen in such a way that the very best in the world can have rating points exceeding 2000, while the absolute beginners score around 1000 rating points.
Conclusion
In 2003, ten years after the launch of the FIFA/Coca-Cola World Ranking for men’s national teams, women’s football also started to have an objective yardstick for measuring the sporting performance of a steadily expanding number of national teams. By launching the FIFA Women’s World Ranking, FIFA hoped to give the popularity of women’s football a well-deserved extra boost.