Monday, 30 July 2012

Olympics, water polo and networks – a slightly biased pondering on chances

The whole world is wildly excited about this year’s olympic games, starting this Friday in London. Every country has its favourite sport, usually the one they are very good at: England has polo, Brazil football, and the United States cheers for just about everything, especially swimming. It is safe to assume, that water polo is the sport that makes the heart of Hungarian sportslovers throb the most. Earlier on, we have taken a look at analysis based on a network representing ball passing habits of football teams, but since the Hungarian team failed to make it to the European Championship, we were unable to conduct a more in-depth analysis. We did however prepare a small summary of the past 4 years olympic water polo results.  Maven7’s money is on Olympic Gold for Hungary, but our objectivity might have failed us on that one. On the other hand, we do have the last ten years results to back up our hunch.
The first picture shows all the games that took place at the last 4 olympics, with the dots representing various countries, green lines showing the winners, and the red ones the draws (i.e. France – Germany). The thicker the line, the more similar the outcomes between the teams were; in Hungary’s case, the strong connections to Greece, the Netherlands and Russia tell us, that we defeated them more than once. The size of the dots increases with the number of games won, whereas the size of the labels grows with the number of games played. The countries that seized to exist since the games are labelled white.

All in all 23 teams and 21 countries earned their quota to the Olympics in the past 12 years. The odd difference between those two numbers is due to changes of regime across Eastern Europe, that varied the names but not the line-up of the leading teams.  The most radical historical alterations happened in countries strongly tied to water polo: Serbia and Montenegro separated, as did Czechoslovakia, and finally the end of the CIS (Commonwealth of Independent States) united team in 1992, including 12 countries came.
The quite dense second picture shows the medal-winning countries. In the next picture the colouring was not calibrated according to Olyimpic regulations. In water polo an olympic gold scores 7, a silver 5, and a bronze 4 points. The yellower a dot is, the more points the country earned (Hungary has 21) in the past 4 Olympics, while the grey ones never made it to the podium.
With 3 gold medals, the Hungarian team is by far the most successful, but the competition is doing just  as well. The Italian, Spanish and Serbian team all did very well, according to the sizes of their dots. Their position in the network tells us, that they are serious challengers, and their experience makes them dangerous opponents, that have beaten us in the past. The biggest losers include  Germany, Greece and  Australia.
For a closer look at our important opponents we re-sized the network. The next picture only shows nations, that have multiple (at least two) connections, meaning that they have faced each other more often, with similar results. Our team has defeated Italy and Greece more than once, but has lost to Spain on multiple occasions. The Croatian team has to look out for the United States and Spain, while the latter one should fear Serbia. There is a definite possibility of meeting the coloured teams in the finals.
In order to have a better chance at pondering on odds, we drew this hierarchical network of the last Olympics. The dashed lines show the qualifying matches, with results on the edges. The green lines point to the winners, the red ones the draws. The dots are coloured according to medals; Hungary-gold, USA-silver and Serbia-bronze.  Hungary won all its matches, except for the draw against Montenegro. It is quite interesting, that we did not have a game against our top rival Serbia. Lets hope that this time the experts are right, and out defeat at the European Championship will not cast a shadow on this years performance, so we can once again stand on our well-reserved spot on top of the podium.

Enjoy the game!
The Team of Maven7

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