Analytics: Debunking Canada’s good defence myth


Canada's drought at the CONCACAF Gold Cup continued after losing 1-0 to Jamaica after a late goal in Group B play in Houston on Saturday (Eric Christian Smith/AP)

This CONCACAF Gold Cup group stage has served up surprises galore in a region typically known for the same powerhouse countries dominating year after year.

For the first time ever all four Caribbean entrants into the Gold Cup—Jamaica, Haiti, Cuba and Trinidad & Tobago—have made it past the group stage. Even more surprisingly Jamaica topped a group with World Cup quarterfinalists Costa Rica while Trindad & Tobago won their group ahead of perennial CONCACAF powerhouse Mexico.

For the North American automatic qualifiers—Canada, the United States and Mexico—it’s been more of a mixed bag. Canada hosted its first ever Gold Cup game, but crashed out after failing to score a single goal. The U.S. topped their group despite looking far from convincing. El Tri on the other hand only managed a second place finish in their group after draws against Guatemala and Trinidad & Tobago.

The struggles of the North American teams in the tournament have dominated much of the narrative pull of thus far so it is worth looking at each team individually to see if the narratives hold up.

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Canada’s defensive form

Canadian coach Benito Floro responded to journalists inquiring about the Reds’ lack of firepower with a jab of his own, “Why aren’t you asking about those other teams not scoring?”

The problem for Floro is that not only was Canada utterly abject going forward they also put up fairly disappointing defensive numbers in the tournament and was probably lucky to have only conceded one goal.

Canada had a pitiful Total Shots Ratio (TSR)—the ratio of shots a team takes relative to the shots they both take and concede—of 0.35. Not only is this overall number a cause for concern, but Canada was also outshot by opponents in all three matches.

Canada averaged 17.67 shots conceded per match across the group stage. As a reference point, Jamaica and Costa Rica both conceded 11.33 shots per game and El Salvador averaged conceding 11 shots per game, leaving Canada with the worst defence in terms of shots conceded by a significant distance.

The story doesn’t get any better for Benito Floro’s “good defence” narrative when we look at Expected Goals (ExpG).

ExpG calculates the probability any given shot will be converted into a goal while taking into account factors such as distance to the goal, angle to the goal, speed of attack and part of the body. For example if a shot has a 30 percent chance of being scored it is worth 0.3 ExpG.

Canada conceded 3.7 ExpG in their three games, which makes the one goal actually conceded look much more like the product of bad finishing from their opponents than the result of any solid defending.

Floro’s claim that Canada defended well during the tournament seems like a pretty flimsy defence of an abysmal performance.

American chances created and conceded

The United States also had an interesting opening three matches. Despite winning Group A with seven points the Americans were outshot 50 to 20 for an almost embarrassingly low TSR of 0.29. That being said in this case the shots don’t tell the whole story.

By sorting the shots into high, medium and low quality chances (in terms of Expected Goals) it becomes clear that while the Americans conceded significantly more shots than their opponents they were pretty much matching them in terms of chance quality. The vast majority of chances conceded by the U.S. in the group stage were worth less than 0.05 Expected Goals, or in other words they had less than a five percent chance of being scored.

This tells us that while the U.S. probably wasn’t the best team in their group they weren’t as completely out-matched as the shot numbers alone would suggest. On the surface they also appear to have an easier path to the final than Mexico, Panama and Costa Rica so it isn’t quite time to hit the panic button yet.

Mexico’s frustrated dominance

Mexico’s game versus Trinidad & Tobago was easily the best of the tournament thus far—ending in a 4-4 draw—leaving the Mexicans frustrated and forced to settle for second in the group.

Despite finishing with disappointing back-to-back draws Mexico was actually quite dominant in the group stage. They finished with an incredibly high TSR of 0.85, even if we omit the Cuba game—in which the Cubans had seven players absent due to a defection and visa issues—Mexico had a TSR of 0.77.

In the game against Trinidad & Tobago in particular the Mexicans were unlucky conceding four goals on five shots on target (with one of them being an own goal).

The nature of Mexico’s results also suggest a bit of bad luck, a 6-0 win followed by 0-0 and 4-4 draws show that the team has the ability to score, the goals just didn’t quite come at the opportune moments. All in all Mexico shouldn’t be too worried headed into the knockout stages after only taking five points out of a possible nine in their opening matches.

It’s been a wild group stage full of puzzling results and some teams we aren’t used to seeing succeed, but as always the scores don’t tell the full story.

Data courtesy of

Sam Gregory is soccer analytics writer based in Montreal. Follow him on Twitter

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