Brazil: better than you think!

Admittedly, it hasn't felt like Brazil has played all that well this World Cup.

The referee seemingly made its two-goal victory over Croatia a more relaxed finish than it should have been; against Mexico, the fourth-place team from CONCACAF, it only managed a draw; and Cameroon was just low-hanging fruit. The host team then took a lot of flak for its play in the Round of 16 against Chile, especially for its performance after halftime. Indeed, Brazil conceded a silly goal on a defensive giveaway, and Chile had chances to win that game.

But I'm here to tell you that Brazil has played better that it has looked. Too often, it seems, the scorelines heavily influence our praise and criticism of what's happening on the field.

Brazil dominated Group A in terms of Expected Goal Differential (xGD), and recorded the second-highest tally of any team during the group stage. Brazil's 1.05 xGD during even (tied) gamestates ranked fifth among the 32 teams. You might have expected better from the hosts, but most teams only played about 130 minutes in such gamestates. That's a big enough sample size to get a general idea of which are the best teams, but too small a sample to split hairs over the top five.

Croatia - June 12th

Against the Croats, a penalty awarded to Fred on what appeared to be a dive marred what was actually a solid performance by Brazil. Up to that controversial call, Brazil had earned 1.4 Expected Goals (xGoals) to Croatia's 0.4, dominating in quantity and quality of shots. Even after taking the lead on the penalty, Brazil still edged Croatia in xGoals the rest of the way, 0.30 to 0.24---a differential that matches what we'd expect of teams that were leading in this tournament.

Mexico - June 17th

Mexico is a better team than their last-second World Cup qualification (and that commentator) would suggest. It led the CONCACAF Hexagonal (the Hex!) in shot ratios and is currently ranked 13th in the world in the Soccer Power Index (though some of that improved ranking is because of their tie against Brazil). Despite a disappointing 0 - 0 tie on the scoreboard, Brazil's 1.4 xGoals again dwarfed that of its opponents. Mexico totaled just 0.5 xGoals.

Cameroon - June 23rd

There's not much to say about this one. Brazil's 1.9 xGD against Cameroon was the third highest discrepancy thus far in the tournament, trailing only France's drubbing of Honduras and Germany's handling of Portugal. It should be noted that both France and Germany enjoyed a man advantage for the majorities of those games.

Chile - June 28th

For Chile, the scoreboard and their well-developed rapport with the woodwork are clear indications that they could have won this game. However, the opportunity creation department informs us that Brazil probably should have won, as it did. 94 percent of this game's shots were taken during an even gamestate, either 0 - 0 or 1 - 1, and Brazil outpaced Chile during that time by a full expected goal. Even after halftime, when Brazil looked disorganized and sloppy, it still edged Chile 1.1-to-0.7 in xGoals.

Perhaps Brazil has not "looked" the part of tournament favorites during its first four games, but its shot creation numbers suggest it is definitely playing like one of the best teams. Add that to their pre-tournament resume, throw in the home-field advantage that's not going away anytime soon, and there is little doubt that Brazil is still the favorite to win this World Cup---maybe not with a majority of the probability, but definitely with a plurality.

The Manaus Effect

During the United States' game against Germany on Thursday, it was hard to go 10 minutes without hearing Ian Darke or Taylor Twellman mention Manaus and its effect on the players. The US Men's National team played its previous game against Portugal in the "Jungle City," as did Italy, England, Croatia and Cameroon, before each dropping three points in their next games.

Business Insider pointed out that those first four teams to play in Manaus lost by a combined score of 10 - 3, though it conceded the tiny sample size. A Washington Post article cited the same statistics, and pondered the possibility of a curse in Manaus. The Independent, based in the United Kingdom, noted on June 24th that each of the seven teams that played in Manaus lost its next game. That was confusing since only six teams had played in Manaus to that point, and only four of those had actually played a "next game." But whatever. #stats Graham Zusi, Sporting Kansas City's All-star midfielder and starter for the USMNT, wasn't having any of it, stating "I don’t think it was that bad to be honest. When it got down to it, at night it cooled off and the humidity wasn’t as bad. I think after about 24 hours the bodies felt great." Hugh Laurie would tell us that everybody lies, especially athletes on record, but there might be something to Zusi's statement. Below is a chart depicting the average temperature, humidity and heat index for each game site. The weather stats were taken from Weather Underground at the beginning of the second half of each game.

City	Games	Temp	Humidity	Index
Fortaleza	4	82.4	62%	85.4
Salvador	4	80.2	73%	83.5
Manaus	4	79.3	81%	82.1
Natal	4	78.5	83%	80.7
Cuiaba	4	78.4	66%	79.1
Brasilia	4	77.5	43%	78.7
Sao Paulo	4	69.4	55%	78.3
Belo Horizonte	4	76.1	40%	77.8
Recife	4	77.5	86%	77.8
Rio De Janeiro	4	75.7	71%	76.6
Porto Alegre	4	65.8	71%	75.5
Curitiba	4	64.0	79%	71.5

It's reasonable to theorize that more extreme environments take their toll on the human body, even professional athletes. But if we're going to get serious here, we need to consider all locales that were exceptionally uncomfortable. Manaus actually ranked third in average heat index, and had a lower average humidity than fourth-place Natal. Italy and England were the first to play in Manaus on June 14th and sparked the notion that it was a hell hole. But while they were duking it out in Manaus, Costa Rica and Uruguay were playing in Fortaleza, number one on that list up there. Though it was less humid to start the second half in Fortaleza, it was actually hotter, and Fortaleza's halftime heat index beat that of Manaus by a few points, 87.3 to 84.6.

It turns out that teams which most recently played in Natal, Salvador or Fortaleza---the other three extreme locations---did alright. Those teams outscored their opponents by a combined five goals. That makes it hard to believe that the conditions of Manaus were responsible for the downfalls of Italy, England and Croatia, though that still leaves the possibility of a non-weather-related curse.

To make this a legit study, there are some other factors we need to control for, and that is why God invented linear regression. Using ESPN's (Nate Silver's) Soccer Power Index, I controlled for each team's overall ability, and then I measured the effects of extra rest and past-game heat index on the goal differential outcome. The output is below:

Variable	Estimate	P-Value
Intercept	-0.37	15.8%
SPI Ratings Differential	1.01	0.1%
Additonal Days Rest (home)	-0.21	68.1%
Heat Index Differential	0.01	74.3%

If you're not a linear regression kind of person, then basically what that chart up there says is that neither the heat index of the teams' past games nor any rest discrepancy seemed to matter during this tournament. At least not in terms of goal differential. But we know that goal differential is finicky, and Expected Goals are a better indicator of team performance. Good thing we've got our World Cup Expected Goals data up and running! If we measure team performance by some Expected Goal Differential statistics (xGD), then we get these linear regression outputs:

Expected Goal Diff	Estimate	P-value	Even Expected Goal Diff	Estimate	P-value
Intercept	-0.06	61.9%	Intercept	0.01	88.4%
SPI Ratings Differential	0.46	0.1%	SPI Ratings Differential	0.34	0.2%
Additional Days Rest (home)	0.13	57.0%	Additional Days Rest (home)	0.17	37.0%
Heat Index Differential	0.00	79.7%	Heat Index Differential	0.00	86.3%

Again, regardless of whether we look at overall xGD or even-gamestate xGD, there are no statistically significant effects due to extreme heat index figures from past matches. Expected Goals data are obviously not a direct measurement of how heat impacts the athletes' bodies, but they should be a stable representation the teams' relative strengths during a match.

The Swiss were the last team (that is still in the tournament) to play in an 80+ heat index environment, but I wouldn't expect that to matter much based on what I've shown above. What will matter is that Argentina is much better. Talent has trumped the heat index so far this World Cup.

Tim Howard's odd odyssey against Ghana

The United States match against Ghana felt odd, didn’t it? After years of focus on ball possession the United States could barely string together consecutive passes. After all the worrying about the inexperienced defense, the backline held like a tight string and almost pulled off perfection against an onslaught of attack. But the combination of those two circumstances, coupled with a remarkable early goal by Dempsey led to a very odd night for Tim Howard. Howard actually led the USMNT in touches in the match with 61. A goalkeeper. With touches. So far, the 61 touches leads the World Cup for a goalkeeper. The average has been 32. The second highest was Bravo’s 58 touches during Chile’s 2-0 smashing of Spain. The games were similar in that both Chile and the United States scored first against a team that would ultimately dominate possession. That can and did lead to an odd night for our goalkeeper.

In the Ghana match, Beasley was second to Howard with 60. The 102% ratio of goalkeeper touches to highest player touches is also the highest of the World Cup. But that got me thinking. What is a typical ratio?

I looked at all 20 games of the World Cup played through June 18^th. The average ratio was 45% goalkeeper touches to highest player touches. The standard deviation so far is 20%. That puts Tim Howard’s number at 2.8 standard deviations from the mean. Assuming a normal distribution, that implies the goalkeeper should have the most touches on a team just once in 400 games. That’s less often than once per MLS season. So it’s not unheard of, but it’s pretty irregular, and it definitely highlights some of the oddities of the United States win over Ghana; an early goal and a team that fails to keep possession, resulting in a backline and goalkeeper that were very busy.

Taking the touches analysis a bit further, I looked at the influence of certain positions having the most touches. I split the outcomes into games where Goalkeepers or Defenders had the most touches and where Midfielders or Forwards had the most touches. Some interesting things pop out even though the sample size is small.

Leader in Touches	Team-Games	Goals For	Goals Against
GK or D	19	1.37	1.84
Mid or FW	21	1.62	1.19

There is a pretty clear advantage so far when a midfielder or forward leads the team in touches. Certainly there is a cause and effect issue at play here. Is this the result of one team’s dominance over the other, or is it really more important to have the ball at the feet of the attacking players more often?

Of the 20 World Cup matchups thus far, eight of them included one team being led in touches by a defender while the other team was led in touches by a midfielder or forward. In those games, the team which was led in touches by a midfielder or forward produced a record of 5-2-1 (W-D-L).

Again, it’s too early to read too much into this data,  but it will be interesting to follow through the tournament. The data does open up thoughts of tracking where touches are occurring on the pitch and how that might help describe outcomes or predict them.

No matter what, Tim Howard was more involved than any player for the United States on Monday night. Neither he nor the American fans felt comfortable throughout the match, and the touches data justifies that sentiment.