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© 1998-2000 Jostein Nygård & Herman De Wael
Last updated 02/07/2000
If you have any comments, email me at soccerarchive@netcom.no
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How are these ratings calculated?
How is the average calculated, is it a simple average?
How often is the rating updated?
What matches are included?
How far back in time do you go?
Why are all these coefficients put at the values they are?
Why "soccer" and not "football" in the name of the rating?
List of tournaments considered to be "official"
Calculation of home advantage
What's new?
Something still unclear? Send a note
How are these ratings calculated?
These ratings are calculated iteratively :
A) In the first iteration, all teams get value 5.00
then :
A1) for every match, for each team, a score is calculated as the sum of
- the goal difference
- the opponents' value
- the correction for venue (+0.75 for the away team, -0.75 for the home team, 0 if on neutral
ground)
- the score for winning of penalty shootout (+0.5 for the winning team, -0.5 for the loser)
A2) then the score is adjusted by:
- time played (extra time counts as 1.333 match)
- importance of match (friendlies only counts as 0.5)
Thus the score for France in the World Cup final was 7.50 (5.00 + 3 - 0 - 0.5), the score for
Brazil being 2.50 (5.00 - 3 + 0.5).
A3) For every team, the average is calculated of all these scores. This becomes the first
approximation of the rating for that team. For Brazil, this first average was 6.47 (after the
1998 World Cup final), for France, it was 6.10.
B) In the second iteration, the value of each team is set at the rating after the previous
iteration.
B1) All the scores are recalculated.
The score for France in the final now becomes 8.97 (6.47 + 3 - 0.5), for Brazil 3.60 (6.10
- 3 + 0.5)
B2) These scores are again averaged.
Brazil's average goes up to 6.81, France's to 6.67.
C) This whole process is repeated some 40 times, after which the changes become so small that
they are barely noticeable.
How is the average calculated, is it a simple average?
No, the average is weighted. All scores are given a specific weighth. This weighth depends on
three factors:
- the "importance" of the match : friendly matches have half the weighth of official matches;
- the time of the match : all matches from the current semester count as whole, but those of
last semester have their weighth reduced to 70%. The semester before that has a weighth of
49% (.7^2), before that of 34.3%, then 24% and so on back in time.
How often is the rating updated?
The rating are updated once a month.
What matches are included?
All matches that are considered to be a "full international" by both national sides.
From these, certain matches are dubbed "official":
- Competitions held by FIFA (World Cup, Intercontinental Cup) or one of the confederations (African
Cup of Nations, European Championship, etc.) as well as qualification stages to these competitions
(Polynesian Cup, UNCACAF Tournament, etc.). For a complete liste go here.
All other matches are called friendlies, and count for only half the weighth.
How far back in time do you go?
In theory we could be going back to the beginning of international matches (in 1872).
For practical reasons, we have gone back only until the second half of 1994.
Don't forget though, that this semester's matches only have a weight of 8.23% of those
for the first semester of 1998.
Why are all these coefficients put at the values they are?
- The coefficient of 70% is used in accordance with a value Herman used to great success in his
cricket ratings.
- The home coefficient of 0.75 is used after we checked the data and found that on average the
home teams score 0.72 goals more than the away teams. To see calculations go here.
- The score for a penalty shootout win (0.5) and the importance of friendly matches (0.5)
have been put at the most simple number we could find that satisfied what we wanted it to do.
A penalty shootout should count for less than 1 goal, but more than 0, and we found no reason not
to put it at 0.5. As to the importance of 'friendly" matches, there too we decided that half the
value was probably close to correct.
- The coefficent of extra time of 1.333 is simply 120 minutes (full time + 30 minutes extra time)
divided by 90 minutes. Matches that are decided by Golden Goal counts for simplicity as
if they played full 30 minutes of extra time.
- The starting value of 5.00 has no influence on the ranking whatsoever, but was chosen in an
attempt (failed for about dozen teams) to put the rating between 0 and 10.
Why "soccer" and not "football" in the name of the rating?
Voetbal, Fussball, Fotball, Ballompié, Fotboll, - only Italian uses a totally different word (Calcio).
In the English language however, there is more than one sport called Football: American Football,
Canadian Football, Australian Rules Football, Gaelic Football, Rugby Union Football, Rugby League
Football, Association Football.
So the only correct appellation is Association Football. But just as many of the others have
abbreviated names, Soccer is the one for our sport.
List of tournaments considered to be "official":
Date Tournament Venue
---------------------------------------------------------------------------------
30/06/00 2002 African Cup of Nations qualifying
19/06/00 - 29/06/00 2000 Oceania Cup of Nations Tahiti
10/06/00 - 02/07/00 2000 European Championship Belgium/Netherlands
08/06/00 - 16/06/00 2000 Polynesian Cup Tahiti
08/04/00 - 15/04/00 2000 Melanesian Cup Fiji
04/03/00 2002 World Cup qualifying
12/02/00 - 27/02/00 2000 CONCACAF Gold Cup United States
22/01/00 - 13/02/00 2000 African Cup of Nations Ghana/Nigeria
06/10/99 - 10/10/99 2000 CONCACAF Gold Cup qualifying
18/09/99 - 30/09/99 1997 Afro-Asian Cup of Nations home/away
03/08/99 2000 Asian Cup qualifying
24/07/99 - 04/08/99 1999 Confederation Cup Mexico
29/06/99 - 18/07/99 1999 Copa America Paraguay
03/06/99 - 13/06/99 1999 Caribbean Nations' Cup Trinidad & Tobago
17/03/99 - 28/03/99 1999 UNCAF Tournament Costa Rica
03/02/99 - 09/05/99 1999 Caribbean Nations' Cup qualifying
25/09/98 - 04/10/98 1998 Oceania Cup of Nations Australia
05/09/98 - 12/09/98 1998 Melanesian Cup Vanuatu
02/09/98 - 08/09/98 1998 Polynesian Cup Cook Islands
31/07/98 - 21/08/99 2000 African Cup of Nations qualifying
22/07/98 - 31/07/98 1998 Shell Caribbean Cup Jamaica/Trinidad & Tobago
10/06/98 - 12/07/98 1998 World Cup France
04/06/98 - 17/11/99 2000 European Championship qualifying
04/03/98 - 10/05/98 1998 Shell Caribbean Cup qualifying
07/02/98 - 28/02/98 1998 African Cup of Nations Burkina Faso
01/02/98 - 14/02/98 1998 Gold Cup United States
12/12/97 - 21/12/97 1997 Confederation Cup Saudi Arabia
04/07/97 - 13/07/97 1997 Shell Caribbean Cup Antigua & Barbuda/Saint Kitts & Nevis
11/06/97 - 29/11/97 1997 Copa America Bolivia
02/04/97 - 25/05/97 1997 Shell Caribbean Cup qualifying
23/03/97 - 27/04/97 1997 UNCAF Championship Guatemala
04/12/96 - 21/12/96 1996 Asian Cup United Arab Emirates
11/08/96 - 27/07/97 1998 African Cup of Nations qualifying
08/06/96 - 30/06/96 1996 European Championship England
24/05/96 - 07/06/96 1996 Shell Caribbean Cup Trinidad & Tobago
17/03/96 - 05/05/96 1996 Shell Caribbean Cup qualifying
10/03/96 - 29/11/97 1998 World Cup qualifying
24/01/96 - 13/08/96 1996 Asian Cup qualifying
13/01/96 - 03/02/96 1996 African Cup of Nations South Africa
10/01/96 - 21/01/96 1996 CONCACAF Gold Cup United States
10/11/95 - 01/11/96 1996 Oceania Cup home/away
21/10/95 - 10/11/95 1995 Afro-Asian Cup of Nations home/away
19/07/95 - 30/07/95 1995 Shell Caribbean Cup Jamaica/Cayman Islands
05/07/95 - 24/07/95 1995 Copa America Uruguay
07/05/95 - 27/05/95 1995 Shell Caribbean Cup qualifying
06/01/95 - 13/01/95 1995 Confederation Cup Saudi Arabia
07/09/94 - 13/12/95 1996 European Championship qualifying
04/09/94 - 30/07/95 1996 African Cup of Nations qualifying
Calculation of home advantage:
Home Away Matches Average
----------------------------------------------
2st half 1994 341 220 219 0.55
1st half 1995 455 307 280 0.53
2st half 1995 407 254 230 0.67
1st half 1996 578 290 313 0.92
2st half 1996 556 354 325 0.62
1st half 1997 734 358 407 0.92
2st half 1997 520 318 301 0.67
----------------------------------------------
3591 2101 2075 0.72
----------------------------------------------
Based on this we put this parameter at 0.75.
What's new?
May 1999
1. We have updated the archive adding almost 90 new matches, as well as removing some matches
that was not full internationals.
2. We have redefined the term "official match", see here. For a complete liste go here.
3. Instead of using 'fixed' rating for the monthly updates, we now use complete calculations for all
updates.
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© 1998-2000 Jostein Nygård & Herman De Wael
Last updated 02/07/2000
If you have any comments, email me at soccerarchive@netcom.no
This page hosted by
Get your own Free Home Page