When looking at the raw underlying statistics of BVB, this season has been beyond successful. The team has scored 50 goals so far this season, a total of 11 more than the expected 39 calculated on Understat. While that may mean that the team has been incredibly lucky going forward, the team has conceded the third least amount of goals with a total of 20, two more goals than both Gladbach and RasenBallsport Leipzig. That is an average of one goal conceded per game, which is astoundingly low, considering a quarter of those goals came within a week against Leverkusen and Augsburg (Both late wins, with the latter being Paco Alcacer’s debut).
And while the 50 goals this season is an astounding number, there is a concept that 538 uses called adjusted goals to update and recalculate that specific team’s SPI or Sports Index Rating, which can be a decent predictor for games.
Taking the segment from 538’s description of “How Our Club Soccer Predictions Work”:
The two other indicators used by 538 to calculate the offensive SPI rating for a certain team are shot based expected goals (or xG), or non-shot based expected goals, a value they calculated through a correlation of possession and passing numbers of a club teams.
Using the concept of adjusted goals, it makes sense that a side would capitulate late into games that they are losing, or that it would be easier to score more goals when the opposing team is a man down (theoretically, sometimes it might not be the case).
Looking back at the Understat numbers, the only area where Dortmund underperforms offensively, is when Dortmund is up by one goal (1.11). When losing by more than one goal, Dortmund underperforms by negligible margins (0.06), while all other times, including game states of zero, negative one (losing by one goal), and more than one (winning by more than one goal) goal differentials, Favre’s Dortmund side over-performs the expected goal numbers. Following the trend of adjusted goals, the largest xG to real goal differential is when BVB has a goal difference of more than one, by nearly seven(!) goals, a total more than what the xG even predicted (4.07) for that particular game situation.
But there might be reasoning to why Dortmund struggles when being a goal up. The other team makes adjustments, sits back in a more compact shape, focuses more on the defensive side of the ball, looking to take advantage on the counter. The spaces that Reus wants to take advantage of in the middle of the pitch are not as available. The runs of Paco, Sancho, and Götze are less likely to pull the back line out of shape. Thinking about the intangibles - the motivation from conceding a goal could make the opposition focus and dig in. It could be a plethora of reasons, but it probably is a combination or sum of the aforementioned factors.
Looking forward, there is little that Favre can do to fix this cyclical problem, other than find new ways to beat a low block side, something that even the best managers struggle at. But as much as teams know that their back lines are vulnerable to late Paco Alcacer cameos, teams might start to look to hang in late in matches and exploit the chaos to scrape the occasional draw against the competition leaders.
What are your thoughts on the problem and what can Favre do to alleviate the problem?