http://clubelo.com/ArticlesArticles on the Football Club Elo Ratingsenrss@schiefler.com (Lars Schiefler)http://clubelo.com/Articles/TheEuropeanCupwinnersandhowgoodtheyreallywere.htmlThe Champions' League and in former times the European Cup has been created to find the champion of the champions, or the best team in Europe. How well does this competition achieve that? The following table shows every European Cup winner since 1956, their Elo rating and rank after the final:...http://clubelo.com/Articles/HomeFieldAdvantageperCountry.htmlThis article spotlights the development of home field advantage in European football. The pure existence of home field advantage already is a mystery, it can be observed in many sports and also in football. We have seen that home advantage has been much more significant in the past, especially the 1970s. We will have a closer look on the development of home field advantage in the European leagues over the last five to seven decades. Applying the new method for calculating home advantage as expl...http://clubelo.com/Articles/AdaptiveHomeFieldAdvantage.htmlThis article describes a new method of determining the home field advantage in club football. As opposed to the static method that has been applied so far, from now on home field advantage will adapt to results every day and will be different in every country and for international games. ...http://clubelo.com/Articles/NewFormulafor2-Leg-Games.htmlThe current method of calculating two-leg games takes into account the aggregate result, increases its weighting and subtracts the result of the first leg. Please see ...http://clubelo.com/Articles/Servermigrationandmorechanges.htmlUntil now, to update Clubelo, I calculated the rankings on my computer and uploaded them via FTP. That meant that if I was on holiday or otherwise busy, updates were delayed. That is why I spent some time migrating and automating the whole site on a server that can do this automatically. This is good news for those of you who care about up-to-date fixtures who like to have more regular updates. Weekend fixtures should be online before the Friday night games kick off. Apart from that, the followi...http://clubelo.com/Articles/Improvingthepredictionmodel.htmlIn the last article, we compared the predictions of the Elo model with the actual average results for each percentile and we found out that it is quite well predicting the outcome of future matches but there is still room for improvement. This article introduces a new prediction model that is based on the Elo system as well as on the Poisson distribution. Finally, the new prediction method is quantitatively examined. Several sources state that the number of goals scored by a team can be describe...http://clubelo.com/Articles/HowaccurateistheElosystemanditspredictions.htmlMany sites offer predictions for football matches, very few of them actually review and publish analyses of their predictions. Having over 260000 football matches in the database, I wanted to see how my system stands the reality check. Does a team really win in 70% of the cases (draw counting as half-win half-loss) if my system estimates the probability at 70%? Let's find out. I went through all the matches in my database with the exception of 2nd leg matches. The reason for this is that teams d...http://clubelo.com/Articles/Themysteriousdeclineofhomeadvantage.htmlThis article shows that home advantage in European club football is massively decreasing since the seventies. When I started this site, the oldest results that were included in the database were from 1993. I used them mainly for calibration and to have evened out Elo values for today's clubs. I discovered that on average, the home advantage is approximately 90 Elo points (measured on a 4-year period between 2006 and 2010). Have a look at ...http://clubelo.com/Articles/Newfeatures.htmlMany new features have been introduced to this site: 1. More games The timeframe of this site extended from the last 4 years to the whole era of international club football and beyond. Click on Data on the right to see details. 2. More information Every game shows now the clubs' Elo values before the game and the exchanged Elo points or a winning probability if the games is still to be played. Two-leg games are grouped now. 3. Better rating system Based on the vast amount of historic results, th...http://clubelo.com/Articles/MeasuringaLeaguesStrength.htmlAn often debated question is what the best league in Europe is. There is no clear answer to that. What is more important, the best teams, the weakest teams? Even an average is not easy to use as the different leagues have different sizes, how can you compare a 16-team-league to a 20-team league? These rankings will use an arbitrary method of ranking leagues: The clubs are ranked in order of their Elo value and summed up by using a weighting of a geometric series with the common ratio of 3/4. Thi...http://clubelo.com/Articles/PromotionandRelegation.htmlClubs that are newly introduced in this system need an initial Elo value to start from. Being relegated is defined here as not playing for one year because of real relagation or - if the league matches are not available - non-qualification for the European Cups. Teams count as relegated if there is already clear that they will not play a match in the covered competitions in the next 12 months. A club that has not played for at least 12 months or enters the system for the first time is a promoted...http://clubelo.com/Articles/Inter-LeagueAdjustments.htmlTeams from different leagues play against each other in European competitions and exchange Elo points. This means that leagues exchange Elo points as well. However, when one observes the leagues' Elo differences over time, it becomes clear that leagues do not exchange enough Elo points just by the few European matches each year. The Elo values will then be very inert and it takes decades for formerly weak leagues to catch up with formerly strong leagues. So these ranking will apply an additional...http://clubelo.com/Articles/Two-LegGames.htmlMost of the inter-league competition in European cups is played in two-leg matches. If the standard Elo formula is applied to these games, a serious problem can arise: A team winning its first leg by a high margin can afford to lose the second leg by a narrow margin and go through to the next round. This will be preceived as an overall victory, the Elo system however will count this as a victory and a loss, which could result in an overall loss in Elo points. This ranking will apply a different ...http://clubelo.com/Articles/HomeFieldAdvantage.htmlIn football as in other sports, the home field advantage has a measurable effect that is taken into account in these Elo ratings as well. If the Elo formulas were applied without any home field advantage adjustment, home teams would win a lot more Elo points than away teams. To counter this effect, home teams have to be rated artificially higher until the expectation to win or lose Elo points is balanced between home and away sides. The following graph shows how many points the home team would w...http://clubelo.com/Articles/WeightIndex.htmlThe weight index determines how many points are exchanged per game. A low weight index (10 or lower) would lead to a long-term-ranking where results from the distant past still have an effect on todays Elo values. A very high value instead would be a good indicator on current shape of clubs and recent results. This ranking uses the weight index that allows the best prediction for the next match. Simulations for every weight index have been performed and compared. At a weight index of 20, the dif...http://clubelo.com/Articles/AdjustmentforGoalDifference.htmlAs football is a game of probabilities, where a weaker team can beat a stronger team occasionally, narrow victories are not as significant as landslide victories. In these Elo ratings, the number of points exchanged will be multiplied with the square-root of the goal difference if there is a winner. For a draw, the factor F stays 1. The square-root-formula is inspired by ...http://clubelo.com/Articles/EloFormula.htmlThe rankings on this page are calculated with the ...