How to normalise goalscoring records over the decades?

Physiocrat

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One aspect of discussion which tends to appear is that goals were easier to come by in different eras so a 20 goal a season record in the 1950s is less good than Italy in the 80s.

Another issue is the relative competition in various leagues - today the gap between the top and bottom, or even mid table, is much greater than it was in the early 90s

The first problem is relatively easy to overcome statistically. Work out what proportion of total league goals in a single season one player scored then multiply by a standard figure, probably the latest EPL total goals total (this should also take into account different number of games per season too)

I'm not sure how account for the relative competitiveness. I had thoughts about the point ratio between league winners, mid-table and bottom but was never confident of how to manipulate it to mean something.


You may find this of interest
@Gio
@Brwned

NB. You can't capture everything in stats it's just doing as much as you reasonably can to aid the discussion as much as possible
 

Pat_Mustard

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A never-nude? I thought he just liked cut-offs.
It's an interesting idea but I have no clue how to make it work. Average goals per match in a league in a given season seems a solid indicator of how difficult it was to score. Worldfootball.net has those stats:

https://www.worldfootball.net/stats/ita-serie-a/1/

https://www.worldfootball.net/stats/eng-premier-league/1/

but even then you could argue that the freak goalscorers distort the stats with their own exploits - Messi and Ronaldo account for 96 goals between them in the 74 Real and Barca matches in 2011-12 La Liga.
 

Physiocrat

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Pat_Mustard said:
but even then you could argue that the freak goalscorers distort the stats with their own exploits - Messi and Ronaldo account for 96 goals between them in the 74 Real and Barca matches in 2011-12 La Liga.
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Yeah, that's certainly true. I should crunch some numbers and see if they feel right. What do you think of the suggested method above? I can adjust it to work with averages if that's what I can work with.

Also, any ideas as to how to normalise for the strength of the league?
 

Brwned

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Physiocrat said:
Yeah, that's certainly true. I should crunch some numbers and see if they feel right. What do you think of the suggested method above? I can adjust it to work with averages if that's what I can work with.

Also, any ideas as to how to normalise for the strength of the league?
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I think you could probably get a good indicator of relative league strength by the proportion of points won (to normalise for varying number of games / 2 or 3 pts for a win) by just the top two teams in the league. The problem is that pretty good indicator might work 80% of the time, but totally skew the stats otherwise!

Your idea of top, middle and bottom I think would have a similar challenge in that it'll undervalue the occasional seasons when an outstanding title winner happens to win convincingly in a very competitive league. But I think with the three data points it should cover off the majority of stuff quite well!

If you pull together some of the numbers as a sample I think you'll get a few folks in here offering some more constructive views - it's difficult to do in the abstract! But I've definitely thought about similar so happy to look into it more once you get the ball rolling.

If it's easily accessible I think Pat's right that we should take the league totals / averages for each league rather than just the English league numbers. But if it's too complicated, you might be able to use the English figures x league competitiveness and capture much of the same detail.
 

Chesterlestreet

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I remember looking up various numbers for individual top scorers in the notoriously stingy Serie A of the 1980s - in connection with some draft or other.

One thing that struck me was how often you'll come across players who post numbers that compare - percentage wise, relative to the total number of goals scored by the player's team - very well to the insane numbers posted by Messi and Ronaldo.

Scoring 14-15 league goals sounds unremarkable (and is, in a sense, since it would be bested by several other players in most seasons) - but when your team's total lies somewhere between 40 and 50...well, there you go. Percentage wise it stands up very comfortably to Messi scoring, say, 46 out of 115 (2012).

ETA

Example:

Altobelli, 1985: 17 goals / Inter 42 goals total (league).

40,5 %

Which doesn't only compare well to Messi's numbers above, it's actually slightly better.
 
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Physiocrat

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A test.

I'm taking Platini's best league scoring record from Juve (20 in 28 in 1983/4) and Messi's from Barca (50 in 37 in 2011/2).

As a proportion of total league goals Platini scored 20/573, Messi scored 50/1050.

So assuming they played in last season's EPL they would have scored

Platini 20/573 x 1072 = 37.4 goals
Messi 50/1050 x 1072 = 51 goals

Platini played 28 out 30 games so played in 93.3% of all the league games. So that means he would have scored 37.4 goals in 35.5 games in the EPL last season.

Messi played 37 out of 38 games (EPL is 38 game season) so he scores 51 goals in 37 games.

Platini's goal's per game ratio is then 1.05 goals per game (un-adjusted it is only 0.71)
Messi's goals's per game ratio is then 1.38 goals per game (un-adjusted it is 1.35)

Now an attempt to adjust for league strength-

In 1983/4 in Italy the Top 2 got 17.5% of all total points
In 2011/2 in Spain the Top 2 got 18.3% of all total points
In 2018/19 in England the Top 2 got 18.2% of all points

So if Platini plays in a league as competitive as 18/19 EPL he scores -

37.4 x (18.2/17.5) = 38.9 goals

Messi scores -

51 x (18.2/18.3) = 50.7 goals

So with total goals and competitive adjustment (so as if they played in the EPL 18/19)

Platini scores 38.9 goals in 35.5 games, goals per game 1.10 (unadjusted it is 0.71)
Messi scores 50.7 goals in 37 games , goals per game 1.37 (unadjusted 1.35)

For a little more context Salah, Mane and Abameyang only scored 22 goals each last season.

Messi's goal record is 1.5% better than he originally appears [(1.37/1.35)-1]
Platini's goal record is 55% better than he original appears [(1.1/0.71)-1]

So Messi is still the better goalscorer (I think few would have doubted that) but Platini is a lot better than it would first appear.

Thoughts? @Brwned @Gio @Chesterlestreet @Pat_Mustard
 
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Chesterlestreet

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Hm. League strength strikes me as a key element here - or rather team strength and league strength, some kind of method for determining that. Not sure what the best way to do that is. You pretty much have to factor in variables beyond sheer numbers, I think. A shite league, relatively speaking, can be highly competitive (again, relatively speaking).

A less competitive league can also be of a high overall quality - only with one or two exceptional teams in it, for a shorter or a longer period. None of that is easily reflected in pure numbers.
 

P-Nut

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Chesterlestreet said:
Hm. League strength strikes me as a key element here - or rather team strength and league strength, some kind of method for determining that. Not sure what the best way to do that is. You pretty much have to factor in variables beyond sheer numbers, I think. A shite league, relatively speaking, can be highly competitive (again, relatively speaking).

A less competitive league can also be of a high overall quality - only with one or two exceptional teams in it, for a shorter or a longer period. None of that is easily reflected in pure numbers.
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Doesn't the % of total league points adjust for that?
 

Physiocrat

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Chesterlestreet said:
Hm. League strength strikes me as a key element here - or rather team strength and league strength, some kind of method for determining that. Not sure what the best way to do that is. You pretty much have to factor in variables beyond sheer numbers, I think. A shite league, relatively speaking, can be highly competitive (again, relatively speaking).

A less competitive league can also be of a high overall quality - only with one or two exceptional teams in it, for a shorter or a longer period. None of that is easily reflected in pure numbers.
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I don't see how we can factor in league strength in any reasonable way. That would always be contextual and up for debate.

What do you think of the Platini and Messi adjustments? Does it makes sense/seems reasonable?
 

Chesterlestreet

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P-Nut said:
Doesn't the % of total league points adjust for that?
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Well, the sheer numbers won't reflect the actual quality of the teams. You'll see if the league is uncommonly unbalanced, but that's different.

The numbers posted above (Serie A, 80s - La Liga, 2010s - PL present) are similar. But so are the numbers for a randomly chosen season in the Polish top flight. The percentage is 18,3 - identical to La Liga 2012.

Looking at G. Muller at the moment - just for kicks: the percentage for the Bundesliga in 1972 is slightly lower than the ones mentioned above, at somewhere south of 16.

Not sure what this tells us, if much at all.

Intuitively, it seems relevant that the gap between Real/Barca and the rest is vast in 2012, both in terms of points and goals scored. It reflects the individual gap between Messi/Ronaldo and - say - Falcao: he scored 24 in 2012. A. Madrid scored 53 in total, meaning that his percentage of the team's goals was better than both Messi (just about) and Ronaldo. Not sure what that tells us either.
 

Chesterlestreet

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Physiocrat said:
Does it makes sense/seems reasonable?
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It seems reasonable in the sense that Platini's goal scoring impact is clearly much higher, relatively speaking, than a straight comparison of the raw numbers would indicate.

But I'm not sure you need that top 2/total points percentage - it's not clear to me what that adds. Like I said, if the league is very unbalanced, this will be reflected in said percentage. But even an obvious two-horse race like la Liga 2012 won't yield anything spectacular in that regard - as demonstrated above.
 

Physiocrat

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Chesterlestreet said:
The numbers posted above (Serie A, 80s - La Liga, 2010s - PL present) are similar. But so are the numbers for a randomly chosen season in the Polish top flight. The percentage is 18,3 - identical to La Liga 2012.
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I thought they would be more different but it did make a reasonable difference to the goal tally. Maybe there's a different measure of that we could use, maybe top 4 might be more different. Would have to try a few out.
 

Chesterlestreet

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Physiocrat said:
I thought they would be more different but it did make a reasonable difference to the goal tally. Maybe there's a different measure of that we could use, maybe top 4 might be more different. Would have to try a few out.
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Top four (points):

Spa, 2012 - 29,6%
Ita, 1984 - 32,2%

Spain's top four less dominant, then, in spite of it including Real/Barca.

Also, top 2, same method but substituting points for goals:

Spa, 2012 - 22,4%
Ita, 1984 - 18,3%

Bigger discrepancy there. Real/Barca grabbing a significantly larger percentage of the total compared to Juve/Roma (for that year) - but still nothing positively outrageous, I'd say.

Anyway, the top four/points comparison is telling: on paper, just looking at that particular percentage, the conclusion should be that Spain 2012 is more competitive (top four grabbing less of the total points) - but that seems like a very odd conclusion given what we know: Real and Barca were utterly dominant. There's a gap of thirty points between Barca (2nd) and Valencia (3rd). And then a gap of twenty between Valencia and the relegation zone.

Yeah - fun with numbers, I guess, but the value of it...I dunno.
 
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Chesterlestreet

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Comparison of goals per game, top four:

Ita, 1984:

1 1.9
2 1.6
3 1.6
4 1.2

Spa, 2012:

1 3.2
2 3.0
3 1.5
4 1.4
 

Physiocrat

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@Chesterlestreet It seems then just normalising for the total goals scored in the season is probably the best way to go and leave the rest for verbal debate. I am quite happy with the way that turned out
 

Chesterlestreet

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Physiocrat said:
@Chesterlestreet It seems then just normalising for the total goals scored in the season is probably the best way to go and leave the rest for verbal debate. I am quite happy with the way that turned out
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Yeah, I think so. And in some cases that will indeed be illuminating - because people these days do have a tendency to look blindly at raw numbers without considering context at all.

On a side note, I'm not advocating using my individual/team ratio as a meaningful indication of goal scoring prowess - just to make that clear. A half decent finisher could post incredible numbers (percentage wise) in a shite team: There are relegation teams in the Serie A of the 80s, to stay with that league/era, that scored a shockingly low number of goals. A mainstay up front in such a team could very plausibly score well north of fifty percent - which would indicate just about nothing.
 

Physiocrat

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Chesterlestreet said:
On a side note, I'm not advocating using my individual/team ratio as a meaningful indication of goal scoring prowess - just to make that clear. A half decent finisher could post incredible numbers (percentage wise) in a shite team: There are relegation teams in the Serie A of the 80s, to stay with that league/era, that scored a shockingly low number of goals. A mainstay up front in such a team could very plausibly score well north of fifty percent - which would indicate just about nothing.
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That's definitely true
 

Chesterlestreet

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A worthy project would be to make a comprehensive overview (something of the sort has been done, but nowhere near definitive) of players who have scored crucial goals in matches over the years.

Finals (obviously).
Big knockout matches (late stages and/or against top level opposition).
League encounters against rivals for the title.
League encounters where the result was crucial.

In a draft context it might be more interesting to know which player is more likely to step up and hit the net in a big match - rather than knowing which player is more likely to, statistically, hit the net in any old match.
 

GodShaveTheQueen

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Physiocrat said:
@GodShaveTheQueen Did you ever finish the thesis?
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I gave up less than halfway along the way mate.

I think this is too tough a project that needs a Phd level of research. (Not exaggerating)

Way too many parameters to consider and way too much data required.

I don't think pure stats and just playing with the numbers is the way to go with this.
 
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Physiocrat

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GodShaveTheQueen said:
I gave up less than halfway along the way mate.

I think this is too tough a project that needs a Phd level of research. (Not exaggerating)

Way too many parameters to consider and way too much data required.

I don't think pure stats and just playing with the numbers is the way to gave with this.
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Fair enough. I still think though adjusting for total goals per season helps quite a bit as a first step.
 

Physiocrat

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GodShaveTheQueen said:
I'd agree with that but but Platini's escalated numbers seemed a bit unreal to me.
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Without the league competitiveness adjustment it is 37 goals in 36 games. That seems quite plausible to me given it is a GOAT at his peak whose goalscoring marked him out from other passing based 10s.
 

Gio

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Physiocrat said:
Without the league competitiveness adjustment it is 37 goals in 36 games. That seems quite plausible to me given it is a GOAT at his peak whose goalscoring marked him out from other passing based 10s.
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Aye, Platini deserves all the kudos he can get for his outrageous goalscoring return in the 1980s. Hard to think of anyone else whose goalscoring was as impressive during that decade when you factor in the context in which they operated.
 
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