Why Chelsea score so few goals and how crucial big chances are

At Spurs, big chances account for 15% of their shots, which means that from 15% of the shots they take comes 43% of their goals. The important of big chances become clear. At Barcelona, from 23% their shots comes 79% of their goals. At Manchester City from 21% comes 59% and at Napoli from 17% comes 61%. The varying of the numbers aren’t worth paying attention to, what is glaring is that a relatively small percentage of a teams chances are big chances, but at the same time it’s from those big chances that the bulk of their goals would come from, so the more of those big chances they can create, the more goals they’d be able to score.

This does not just apply to actual goals, but expected goals too. Using the same five clubs mentioned above, non-penalty big chances account for at least 32% of their total xG. Again, note that the actual figure would be way higher because very few big chances are actually 0.25 xG. At Barcelona non-penalty big chances account for at least 42% of their xG, for Napoli and Arsenal it’s 34%, and for Manchester City it’s 40%. Again, the numbers vary because every team is different, but the point still stands. At Barcelona, 23% of their shots account for 42% of their xG and 79% of their goals. Seems like an extremely important 23%. And the 23% are the big chances.

Chelsea has had a problem creating a volume of clear cut chances befitting for the amount of the ball they get per game. This season it has been much worse. 46% of Chelsea’s goals this season are from non-penalty big chances. 17% of their shots are from big chances, and 39% of their xG are from non-penalty big chances. This is normal, in terms of proportions, but what makes it a problem, is the number of big chances it has created relative to some other teams in Europe.