The Group of Death

When the World Cup draw was announced back in December, fans of the four teams in group G (the group that includes the U.S.) were all justifiably upset. Group G was called the "group of death" due to its apparent difficulty. This sort of group seems to occur in every World Cup. In this post, we'll examine whether the U.S. is truly in the hardest group as well as which team has the hardest and easiest paths to the round of 16. Then, in the post tomorrow, we'll look at why the groups wind up so imbalanced so often and consider a possible reform that would balance the groups out.

First, is the U.S. truly in the hardest group? To answer that question, let's look at the quality of each group. To do that, I will use the Elo ratings as of Monday, June 2, 2014. I chose the Elo ratings because I think they are a more accurate measure of a team's strength than the FIFA ratings and because Brazil's ranking by FIFA is artificially low because they didn't have to play any qualifiers, earning them fewer points in the FIFA rankings. For each group, I put in the Elo ranking for each team and then made two calculations for the group: average rank and the standard deviation of the rank. Both measure how hard the group is, but in different ways. The average rank value tells how well-ranked the teams in the group are overall: the lower the number, the harder the group is in general. The standard deviation of rank value tells how spread apart the teams within the group are. A lower value indicates the teams are all ranked around the same value, making the group harder as well, since teams of similar strength are grouped together, making winning more difficult. Below are the results.
Group A (Brazil, Mexico, Croatia, Cameroon) -- Avg: 23.5, SD: 20.2
Group B (Netherlands, Chile, Spain, Australia) -- Avg: 12.25, SD: 12.2
Group C (Colombia, Cote d'Ivoire, Japan, Greece) -- Avg: 18.5, SD: 6.2
Group D (Costa Rica, Italy, Uruguay, England) -- Avg: 14.5, SD: 10.3
Group E (France, Ecuador, Switzerland, Honduras) -- Avg: 23, SD: 12.9
Group F (Argentina, Nigeria, Iran, Bosnia-Herzegovina) -- Avg: 23.25, SD: 11.56
Group G (Germany, USA, Ghana, Portugal) -- Avg: 15.25, SD: 13.6
Group H (Belgium, Algeria, Russia, South Korea) -- Avg: 31, SD: 17.0

So, is the USA in the hardest group? The answer is no. Group G, which includes the USA, is indeed a hard group, but it is not the hardest group by average ranking. That honor belongs to group B, with three teams in the top 10 in the current Elo rankings. Moreover, it is not the hardest by similarity in rank. That group is C, with Colombia at #8 and then 3 teams in the 20s. The USA's group is the 3rd hardest by average and the 6th (of 8) hardest by similarity in rank. So, the U.S. is not in the "group of death." Group B is probably the group of death because of its three really strong teams. True, the USA is in a difficult position, but so are the teams in groups B, C, & G. In other words, half of the groups are "groups of death" for the teams in them, except for maybe Colombia, which has an apparently easy path through to the round of 16.

The easiest groups are quite a contrast to the strong groups. Group H is the weakest by average rank. It has an average rank of 31, with 0 teams in top 10, and two teams that are ranked 42 & 53. The easiest group by similarity is group A, with a standard deviation of 20.2. Although group A does have the #1-ranked Brazil, it also has #56-ranked Cameroon. Group E is almost as easy as group A, also having 0 top-10 teams.

 Leaving groups aside a second, let's look at which teams have the easiest and hardest paths to the round of 16 based solely on the draw. To calculate this, I subtracted each team's rank and the rank of each of its fellow group members. Then, I averaged the differences. I also calculated the standard deviation of the differences. A team with a large negative number is highly likely to advance, as it is far better-ranked than its opponents. This is doubly true if the standard deviation is small, meaning that all of a given team's opponents' ranks are all near the average. The team with the hardest path out of the group stage is, unsurprisingly, Cameroon, with an average ranking difference of 43.3, that is, they are ranked 43.3 points lower on average than their opponents. Their standard deviation of 8.5 also suggests that most of their opponents are ranked about 43 points above them. The USA has the 14th hardest route to the round of 16 based on the draw, with an average of -3. The USA's standard deviation is 15.6, though, so the rankings of their group opponents are a bit scattered. The team with the easiest path the round of 16 could be one of three different teams: Brazil, with an average of -30 and standard deviation of 17.8, Colombia, with an average of -14 and a standard deviation of only 1.6, or Argentina with an average of -26 and a standard deviation of 3.7. Based on the overall data, I'd say it's Colombia, then Argentina, with Brazil having the 3rd easiest time.

So, what we've seen is that, despite the hype, the USA is not the "group of death," the hardest group in the World Cup. They are in a difficult group, but it is not the hardest. The U.S. can make the round of 16, provided they win at least one game and don't lose any by large margins. We've also seen that some groups are far more difficult than others. The reason for that will have to wait until tomorrow, when we will look at the group selection process.