Accurately identifying finishing ability isn’t as straightforward as we might think, and over large enough samples the differences between most players aren’t hugely significant or as obvious as they appear to the eye.
Only an elite few consistently outperform what would be expected of an average player. Even Cristiano Ronaldo, whose finishing is often quoted as his biggest strength, has under-performed (scored less than) his expected goals (xG) total in each of the last 3 seasons.
Perhaps he, and other top forwards, should be given more credit for their ‘chance-getting' ability, rather than their perceived ability to finish chances.
Fortunately for us, we at Football Whispers have ‘post-shot' information, which in this case refers to the placement of each shot. Using this as a feature in our expected goals model gives what is known as ‘post-shot expected goals', and by subtracting a shot's original xG from its post-shot xG we can calculate how the shooter’s finishing increased or decreased their chances of scoring.
One season is a small sample size to try and draw conclusions about a player’s finishing ability. To try minimise the role of variance, only players with 55 or more shots in the 2017/18 Premier League season are included below.
No player has increased their xG through finishing more than Mohamed Salah has in the Premier League this season, and this helps explain why he has over-performed relative to the quality of the chances he's been getting. The Premier League player of the year managed 31 non-penalty goals from 20.2 xG and 24.3 post-shot xG on his way to the Golden Boot. Even accounting for finishing ability, this difference is unlikely to be sustainable in the long run.
Nobody would be surprised to see Harry Kane feature highly on this list, but despite finding the back of the net 27 times (not including penalties), that isn’t the case. Salah's main rival for the Golden Boot added just under half a goal to his goal expectation over the course of the season. Kane had the best chances of anyone in the league, and took them at around the expected rate rather than over-performing with his finishing.
Kane's biggest strength is his ability to get shots away, taking 5.4 per 90 minutes, a full shot above anyone else. Interestingly, the three top scorers from outside the box – Kevin De Bruyne, Xherdan Shaqiri, and Riyad Mahrez – are all within the top seven in terms of xG added.
While the notion that long-range shots aren’t very efficient is becoming more widely accepted, these players show that this might not always be the case. Sixty-four per cent of Shaqiri's shots this season came from outside the penalty area, with his shot placement almost doubling his xG from 3.6 to 6.4. Reportedly available for just £12million, this could prove to be a valuable skill for a side that gifts him more shooting opportunities.
Watford's Richarlison is the stand-out player down at the opposite end. His 10.7 expected goals is hugely impressive for a 21-year-old in a debut Premier League season, but wasteful finishing practically cuts that in half to 5.7. The fact that he's getting into the right positions is encouraging but, in order to take a step up to the next level, he'll have to improve on this season's finishing.
Until now, we've just looked at an aggregated total over all of a player's shots. Reducing this to an average per shot is a fairer method of isolating finishing ability as it corrects for differing shot quantities:
Shaqiri now leapfrogs Salah into first, while Manchester City's Gabriel Jesus also stands out from the pack. Christian Benteke finds himself rock bottom here after a woeful season in front of goal where the Belgian scored just two non-penalty goals from 31 appearances, 0.12 per 90 minutes.
An average player would have been expected to score roughly ten goals from those chances, although Benteke's finishing lowered that to 6.4. On average his shooting reduced the probability of scoring by 7.5 per cent, which had quite an impact over a season's worth of shots.
Sadio Mané‘s season has been described by sections of Liverpool’s fanbase as underwhelming, with the general consensus being that he hasn’t really kicked on from his impressive debut season at Anfield. Salah’s otherworldly form has unsurprisingly taken most of the limelight and sets the bar even higher than usual for those around him.
Mané’s pre-shot xG total this season (11.9) was actually higher than that of Roberto Firmino (9.4), but including shot quality almost exactly reverses these, putting Mané on 9.4 and Firmino on 11.4. On average each of Mané’s shots decreased his chances of scoring by 3.7 per cent, with Firmino’s increasing his by 3 per cent.
Dele Alli is another player whose season seems to have fallen into the disappointing category. Last season the Spurs attacker scored 17 non-penalty goals compared to just nine this season.
A potential reason behind this appears to be worse finishing. He went from increasing his chances by three per cent per shot, and his overall xG total from 12.5 to 15.2, to decreasing by 3.5 per cent per shot and bringing his total xG down from 10.1 to 7.7. Alli's change in fortune highlights the need for caution when using small samples to judge players as finishing can be prone to fluctuation season on season.
This makes it difficult to draw concrete conclusions, but there are a few things we can say with confidence. Firstly, Benteke has had a terrible season in front of goal. His finishing has had the worst effect of any Premier League player and contributed to Crystal Palace’s record-breaking early season scoreless run. Richarlison’s shooting has also been wasteful, but at his age he has time on his side and there’s certainly hope for improvement.
At the other end of the scale, Shaqiri and Jesus were the best finishers on a per shot basis while Salah combined high-quality shooting with a high quantity of chances to gain the most xG added in the league.
Importantly, though, goalscoring isn’t only about finishing chances. It’s mainly about getting into the right positions to score and being able to get the shots away. Kane finished the season with the highest total xG (and post-shot xG) despite finishing at a barely above average level.