Games such as Manchester City’s 7-0 win over Norwich last weekend can be problematic for soccer analysis. Most models use goal differential rather than points as final output. Even though this provides a more robust output set and neutralizes “luck factor”(teams that win by wider margins are less likely to be lucky winners) to a certain degree; it creates other problems. I doubt teams are trying to maximize goal differential after they are ahead by three goals or so. However, this rather important but technical matter is not what this post is about. Instead of talking about modelling I am just going to propose an alternate and somewhat fun(?) way looking at goal scorers along the same lines. I am going to use current Serie A Season to get from standard Goals scored to what I call PIG and PIGGy scores and finally introduce the Crispy Bacon Award.
In their book The Number Game, Anderson and Sally talk about marginal point contributions by goal. To summarize if a player is scoring the 1st or 2nd goal of the team he is contributing significantly more than scorers of later goals. Then they rank the EPL players according to their value with the new metric. The approach is interesting but unfortunately falls short of defining important goals. Not all second goals are created the same. A second goal scored when the game is 1-1 is much more important than a goal score while the game is being lost 5-1.(T The real target should be not weeding out later goals all together but defining important goals (IG) by looking at sequence of scoring. (Another important factor to consider is timing of goals which I am disregarding) . Any goal that breaks the deadlock or balances the scoreline should get +1 IGs . Goals that double up the difference or reduces it to one will get 0.5 IGs and so forth. After the 4th goal all goals will be awarded 0.125 IGs. These IG scores roughly correspond to marginal points but with my approach one can have a game with marginal points higher than 3. A game that ends 3-2 can have 5 IG’s if all goals are score alternately or can have 2.5 IGs if Team A first scores 3 goals(1+0.5+.25=1.75 IGs ) to concede 2 goals later(0.25+0.5=0.75 IGs). So how does IG look for Serie A players who score 6 or more goals this year (as a rule I only include players who scored more goals than half the rounds played e.g. if 11 rounds have been played minimum is 5.5 goals ):
Jersey boy Rossi is the current top goalscorer in Serie A with 9 goals. Yet Torino’s Cerci is the no.1 IG scorer in Serie A so far this year. But there is one more adjustment to be made until we can crown Cerci Mr.PIG and that is adjusting for penalties (PIG: Penalty adjusted Important Goals). ~70% of penalties end up as a goal. Therefore rather that crediting the penalty taker with the full goal I award them only 30% of IG if they make it; and punish them 70% of IG if they miss it . For example ,if a player is missing a game tying penalty his total will be reduced by 1*0.7= 0.7 PIGs, but if he is missing the penalty while his team is up 2-0 it will only cost him 0.7*0.25=.175 PIGs.
Mr.Cerci drops from first spot to 4th as he already scored 4 penalties this year and missed one. Our current Mr.Pig so far is Palacio but it’s still early in the season. Yet one should note it is much more difficult to catch up to a leader in PIG table than in a vanilla scorers table as scoring 4 against a very weak team in 4-0 blowout will only get you 1.875 PIGs. You have to be consistent week in and week out or wait to score 3 goals in a game that ends 3-3.
PIGs are just totals; and I do not really like totals on their own . It is important to look at per game numbers(PIGG) or more importantly per 90 minutes(PIGGy- y stands for” yeah I made that up”):
In this case not much changed in the rankings; Cerci dropped another spot as Hamsik replaced him. Palacio is the leading Dr. PIGGy as well as being Mr.PIG. If a player finishes the season as top ranked Mr.PIG and Dr. PIGGy he will be awarded the “Crispy Bacon” award. Let’s have a quick look at top 5 players at other top European leagues: (first PIGs)
Not much to point out in EPL but in Spain Ronaldo drops to no.5 and Messi is not on the list (more on them later). In Germany Lewandowski drops from 1st to 11th. Apparently this year he is the king of “garbage time” goals. I have too look at previous years to see if this is a common occurrence. I suspect Anderson and Sally read too much into their metric; I am not sure if ” scoring important goals” is a skill and teams should purchase on these metrics. I have to look at historical numbers to come to a more definite conclusion. PIGGy’s :
Liverpool really has an amazing striker duo; Sturridge leads as Mr.PIG and Suarez as Dr.PIGGy. (Most of this is due to Suarez being out first few weeks). In Spain; Alexis Sanchez surprisingly jumps to No.1 spot while Messi replaces CR7 on the top 5 table. Alexis has also the highest PIGGy of anyone in 4 major leagues. (In France Riviere of Monaco has a super high 1.2 PIGGy- I suspect attacking subs in very strong teams(e.g. Chicharito) will have abnormally high PIGGy’s ) In Germany we can see that Aubameyang is the player who has been scoring the important goals for Dortmund instead of Lewandowski.
One final note to point out is that the first time in years we do not have Messi and Ronaldo at the top of these tables. Both their numbers dropped significantly this year(season is young, so let’s not despair). Below is a chart of their performance in the last 5 years. Messi would have been awarded the “European Crispy Bacon” in every year but 2011-12 when Ronaldo would have have snatched it (His PIGGy was 0.653 vs Messi’s 0.645). Also Messi is a good boy and Ronaldo’s hairdressing expenses are higher. As usual comments welcome @dingosports.