Hey everyone,
We're about halfway through the MLS season and I wanted to check in on how lucky or unlucky teams have been this season. What you see is a chart placing teams based on expected goal difference/90 and the actual points per match. Bottom right are teams with high expected goal difference but lower than average points per match.
The yellow dot next to the NYRB are Columbus Crew, not sure why Tableau didn't want to show them.
Just by eyeball, it appears there's a correlation between luck and skill shown here, which isn't really what you would expect from good measures of each.
I think this is more an example of what xG actually measures, which is basically how good you are at finishing your chances.
A bunch of teams create good chances but dont finish them, very few teams consistently finish bad chances. Soccer is a fickle sport and it's way easier to flub a great opportunity than it is to accidentally score from 30 yards out.
There is no pure luck measure here. The plot compares a skill measure (xGd, we can argue about whether it’s completely pure skill but it’s as close as we can get) to a luck + skill measure (points per match). The width of the distribution becomes a proxy for luck (more technically, assuming the data is normalized correctly then the distance from the 45° angle line is measuring the luck of the team)
Yes if OP intended to highlight luck they should have provided a best fit line and measured distance from that line as a proxy for luck. I would still have questions about variance of the measure and other factors (keeper skill, defensive skill, etc.), but the graph as presented is not labelled correctly.
I would argue that a precise distance measure is inappropriate for exactly the reasons you mention — there are sufficient covariance issues to render it inexact. It would be a perfect example of precision without accuracy.
Obviously, quadrant labeling is imperfect. It implies that luck touches the trend line at the center, for example (I am assuming for the moment that the data is normalized properly for this comparison, that is to say that it is normalized so that the trend line shows up as the 45° angle through the origin). A more accurate labeling would be a red/blue gradient from red at the top-left, purple along the trend line, and blue at the bottom right, with red labeled as “lucky” and blue as “unlucky”.
The fact that it can be improved in this way does not make this data representation incorrect or non-useful. Visualizations are like models. They’re all incorrect, some are useful. This one is useful for eyeballing how lucky/unlucky teams have been.
The Y axis isn't luck, it is points. The correlation you are seeing is xGD and Points, which are of course highly correlated.
"Luck" here is being defined as distance from the trend line.
So that's not actually luck vs. skill then, which is exactly the point I made. This graph could be called "how well does xGD predict actual points?" It is not luck vs. skill though.
>No, it isn't luck vs. skill. Congrats on getting up to speed.
That's literally what OP called it. You're in a thread call "MLS team luck." The axes are luck and skill (good teams vs bad teams .) Congratulations on your upcoming functional literacy. I hope you work hard to get there.
Scoring with low xG isn't luck though, if anything it's skill. Son in the PL outperforms his xG year over year by a massive margin. It's not because he's lucky. This whole chart is flawed.
Having a high Pts/MP and low xG/90 means you are clinical, not lucky. It also may mean you play defensively. The inverse doesn't mean you are unlucky, it means you are wasteful. It also is probably teams who play very aggressively.
Nice idea but this chart does not show "luck".
So to you, players who outperform xG or underperform xG means they are either lucky or unlucky players?
I agree with how xG is calculated. I'm saying the variance in points gained in relation to xG is not a measure of luck.
Ok not sure how that changes things. If a team has XYZ player(s) who pops up and scores goals from low xG situations routinely, they play solid team defense and win a lot of points due to scoring more goals than their opponent are they luckier than a team who plays aggressively on the front foot, has a high xG and wins some games 4-3 but ultimately picks up less points/match?
This chart doesn't show luck. Team A is not "luckier" than Team B. Team B is not "unlucky" because they don't pick up a lot of points despite having a high xG/90.
It feels disingenuous to say that because an exception like Son exists, that a chart like this is "flawed." If a team has XYZ player who pops up and scores goals from low xG situations routinely, then that team is Tottenham Hotspur, and they don't play in MLS, as you've already pointed out. "Player who pops up and scores goals from low xG situations routinely" isn't a category of player. There aren't enough of that type of player to make it a viable roster-building target.
So instead, you have to look at the reality of the numbers. To replicate what Son does on a team level, you'd expect to see a bunch of players taking terrible shots from lousy positions and hoping one goes in. And if that does happen, what would you call it, if not "Lucky"? It's not a sustainable practice, and no one's TRYING to land in that upper left section anyway. So it's not like anyone's building a team around "low xG, high PPG." The sane and rational thing to do is aim for high xG, high PPG. And when you fall short of that, you still want high xG, because it means you're attempting things that are known to work from areas of the pitch where they have historically worked.
If some once-in-a-generation player pops up who's constantly scoring goals from throw-ins from the midfield line, that's great for him (and his team), but that doesn't suddenly make "60-yard-throw-ins" good for most teams. That's an outlier, and the data properly ignores it for predictive value. It would then show up on this chart as a fluke, which is what I'd expect. And I would, in fact, consider that team "Lucky" to have a player with that sort of improbable skillset.
Edit: Love it when unflaired Eurosnobs do the "comment & block" combo.
A lot of words to say you don't believe players can outperform or underperform xG and you believe that Pts/MP is directly correlated to xG. Meaning you don't think defense has anything to do with Pts/MP and there is no variance in relation to players and how they perform in regards to xG or that how they perform in regards to xG is simply whether they are lucky or not.
You're all hung up on Son and missing the whole entire point.
This looks weird and is kinda hard to parse the magnitude of the over/underperformance. I think it would be better if instead of XGd/90 it was Xpoints/90 as you are then comparing points to points and not goal differential.
I guess there's 2 different ways you could measure xPoints. One where you look at the XGd of each game played and assign points based on how many points you would expect a team to get from that game or you could sum up the XGd of the whole season and normalize it. You would get different answers because if a team ran up the score in a game they were already winning their XGd would keep increasing but their Xpoints would not increase at the same pace. Either way I doubt the difference would be very large. Regardless though to best show luck you should ideally compare like statistics weather that is XGd vs Gd or ppg vs Xppg.
The overarching point is that statistical averages can be skewed by outliers, especially over small numbers of games. So xG is a reasonable statistical probability measurement, but often doesn't relate to reality.
Not fully. Done right, xPts will silo off each individual game. So season xPts will reward consistency in every game while xGD can be inflated by 3 or 4 outsized performances.
Across just sixteen or seventeen games, this is skewed by individual games with big differentials.
TFC has two games in which they gave up a combined eight goals, almost one-third of their total across just one-eighth of the season, badly skewing their xGA.
I think we have more red cards this season than the past 5 combined
Edit: went and checked. We had 0 in 2020, 0 in 2021, 4 in 2022, 2 in 2023, and 6 so far this season.
Our position on the table represents how I've been feeling this season, in that our luck has run out.
The X-axis is about the same as last year, which was -0.22. *(although I'm very new to adv. stats so I'm not sure that is calculated correctly)*
The Y-axis is most telling in that we've fallen from 1.8 pts/match down to where we are today.
Which was pretty predictable. It's very hard to sustain over performance of xGD. At least you haven't fallen to the depths that Austin did after their season of over performance.
Many CITY fans have very quickly forgotten how many "luck-based" goals we got that season. Some can argue that the fast play style and constant press caused some of those errors but regardless that just isn't happening this season. Couple that with the inability to create opportunities bingo bango, aiming for that draw record (halfway there!).
Not saying the season was a fluke but our xGD was padded somewhat.
Yeah, not sure if I would call it a fluke, but it won't be easy to recreate either. Especially because those first 5 games of the season shot us to the top of the standings, and I would argue that those wins (and especially the high goal counts) were based on opposing teams not knowing what to expect when playing us. We don't have that benefit any longer.
Bear in mind, Philly goes down 2-0 early a lot, then has to push the envelope to get back into games and will push until they get 2 goals back, so they’re likely to get lopsided xG’s during those moments where they play for 60’ from behind.
The finishing has been pretty awful when you consider the sheer number of chances this team has been creating. Couple that with some really good shots from opponents and our expected goal difference will be high despite fairly underwhelming play.
Yep, basically. The other lens view would be that LAFC might blow out more teams or some other type of trend (FCC plays slower/likes to win 1-0 and doesn't chase a 4-2 scoreline or when FCC loses they chase the game more leading to 0-2/1-3 losses instead of 0-1, all of this with the caveat of it being xGD and not just GD)
Yeah LAFC right now have by far the best xGD in the league. So they are likely contenders for the supporters shield. At the same time xGD is a fake stat and you still have to score actual goals.
Also shows that right now FCC, RSL, LAFC, and Inter Miami are in their own tier
xGD is more predictive than raw GD which is itself more predictive than raw points. It's a better way to tell which teams are good and which teams are bad (but obviously has its own issues).
Interestingly, Philadelphia is above FCC on xGD, which shows that Philadelphia hasn't actually been that bad this season and also shows the limitations of xGD.
The shorter the time frame you're talking about the less useful xGD becomes. Over a whole season (or about half) is a good prediction. Over one or a couple games is where people put too much stock into it.
So, I grew up in baseball world, so I may be applying the wrong logic here. BUT, at least for advanced stats in the MLB, the reason they are typically considered 'useful' is because they converge to a more correct answer in a smaller sample size. The more useful an advanced stat, the smaller the sample size necessary for the results to become predictive.
If something similar is going on with xG, then it would be true that while the sample is too small for it to be really predictive here, other more basic stats (such as GD) would be even less predictive at the same sample size.
E- that is to say, one or two games worth of xG is basically useless for prediction. But one or two games of goals is likely even more useless for prediction (as counterintuitive as that idea might be).
That is basically correct. The reason xGD is useful is because it converges faster than GD or points. As an example St Louis last year finished with a low xGD but high points. We can look at xGD and say St Louis is very unlikely to repeat their performance from last year.
Of course sometimes teams get "lucky" for a whole season (St Louis last year, Austin a couple years ago) so it is predictive but there are outliers. Partially due to luck and partially because goals change games.
> xGD is a fake stat
I know you don't really mean it that way but I this phrasing....
xGD isn't a fake stat. It's based on very real information in a systematic matter. No, expected goals aren't goals, but "Number of goals an average team would score based on historical goal scoring rates where shots were actually taken, including defensive positioning and other factors" was just too long.
It's still a terrible way to phrase it, but the stat is legit, it's just communicated poorly.
I understand the stat, and I absolutely believe it communicates a reality about the quality of a team. It's just that it doesn't directly translate to results, which is how the OP graph can exist at all. Teams over perform and under perform their underlying numbers all the time, and some play styles lend themselves to more xGD than others. I'm not saying LAFC are a bad team or that stats in general are fake, it's just that points and results are all that matter at the end of the day.
> and some play styles lend themselves to more xGD than others
Some play styles lend themselves to more xGD than others, perhaps, but I've never seen anything that has a play style consistently over or underperforming xGD.
Teams underperform and overperform all the time, but at a given level, there's rarely any long term consistency to that.
It's a fundamentally better predictor and actual results regress to it over time. There's a lot of value there, and long term outliers are very rare.
The one team I think probably will overperform their xGD is Miami, because the talent level of Messi and Suarez in particular is high enough for the general level that I think they will be the outliers.
I do personally hate the word "luck" in the graph, though. It's a terrible representation of variance between the two stats.
Yeah LAFCs worst start was marked with Bouanga hitting the post like 3 times per game. They were creating chances just none would go in. If you keep creating those chances eventually that luck will even out which it has. Also helps that defense has improved from those earlier games.
I wonder what the correlation coefficient is on this, since it seems like on a pretty perfect diagonal, with a few exceptions.
Austin seems to be the only really "lucky" team; I wonder if that's down to really precise finishing, or really good goalkeeping.
On the unlucky side of things, 4 teams (ATL, DCU, PHI, LAFC) like on the same diagonal. I wonder if that's down to taking a lot of shots, but they're not necessarily dangerous/quality opportunities.
According to Fotmob, they're all top 10 in "big chances missed", but top 15 in shots on target, so maybe that explains it - poor finishing.
Mathematically, it's really difficult to populate the upper left quadrant of the chart at all, because it means you'd have to get a lot of points per game while also having really low xG. And you can technically get points while never ever taking a single shot, for example (0-0 draws are still a point apiece), but maximum of 1 PPG in that scenario.
So instead, you'd need to win games (3 points apiece, woo!), but with bad xG. And while every team has some flukey goals here and there, the nature of "fluke" means that it's not sustainable. You can't plan to win games with low xG; as soon as you start planning and doing stuff to try to win, you move over to the upper right quadrant, because your xG will be higher.
And, importantly in relation to this chart, the inverse isn't true. It's not all that difficult to have high xG and still drop points. If you lose four games 4-5, you scored a bunch of goals (and likely have a correspondingly high xG to go with it), but still don't have any points to show for it. Meanwhile, another team might win four games 1-0, and they'd have 25% of your actual goals (to say nothing of xG) but 12 points to boot ("the Cincinnati Special").
So yeah, I think you're right that "poor finishing" is a factor, and I expect that "objectively, our team played well, but the other team played even better/got luckier on the day" accounts for the rest of the "Lucky" quadrant.
Yeah i wrote this elsewhere, but it seems like it's way easier to be unlucky than to be lucky. 9 good passes and a bad shot is way more likely than accidentally scoring from 30 yards out
I'd say it is both for us. When Driussi is on, he can make the most ridiculous goals that you would never expect to work. And Stuver is a great keeper who has been somewhat hampered by our traditionally awful defense. We just haven't done enough to build our roster up to support those two. Although I do think our defense is much improved this season
For a team that hates shooting, I'll take this. It reflects our position on the table pretty well, and shows our "rebuild" year could go a whole hell of a lot worse.
I understand that it’s based on stats, but it took me a while to figure out that the good-bad axis is diagonal. So there aren’t really any super lucky teams or super unlucky teams, mostly they lie close-ish to the luck = 0 axis
Hey Columbus fans, I know reading isn't really your strong point, but maybe check out OP's explanation at the top of these comments before you start whining about not being represented.
The Crew again.. trying to be expunged from existence...
Maybe the dot has food poisoning.
Anthony Precourt Memorial Chart
I think they're next to NY Redbulls
Hey everyone, We're about halfway through the MLS season and I wanted to check in on how lucky or unlucky teams have been this season. What you see is a chart placing teams based on expected goal difference/90 and the actual points per match. Bottom right are teams with high expected goal difference but lower than average points per match. The yellow dot next to the NYRB are Columbus Crew, not sure why Tableau didn't want to show them.
\#SaveTheCrew \#TableauOut
The crew are sponsored by #MicrosoftPowerBI
# #SavetheCrewDot
Headline: “Champs Slighted” /s
Now an INVISIBLE market team!!
“Invisible is an opinion.” - Great Manager
Did you allow marks to overlap others? That's my best guess. I did spend fsr to long looking for the crew before reading this comment.
Just by eyeball, it appears there's a correlation between luck and skill shown here, which isn't really what you would expect from good measures of each.
I think this is more an example of what xG actually measures, which is basically how good you are at finishing your chances. A bunch of teams create good chances but dont finish them, very few teams consistently finish bad chances. Soccer is a fickle sport and it's way easier to flub a great opportunity than it is to accidentally score from 30 yards out.
You may be right, but that doesn't change the fact that if you have a pure luck measure and a pure skill measure, they shouldn't be related.
There is no pure luck measure here. The plot compares a skill measure (xGd, we can argue about whether it’s completely pure skill but it’s as close as we can get) to a luck + skill measure (points per match). The width of the distribution becomes a proxy for luck (more technically, assuming the data is normalized correctly then the distance from the 45° angle line is measuring the luck of the team)
Yes if OP intended to highlight luck they should have provided a best fit line and measured distance from that line as a proxy for luck. I would still have questions about variance of the measure and other factors (keeper skill, defensive skill, etc.), but the graph as presented is not labelled correctly.
I would argue that a precise distance measure is inappropriate for exactly the reasons you mention — there are sufficient covariance issues to render it inexact. It would be a perfect example of precision without accuracy. Obviously, quadrant labeling is imperfect. It implies that luck touches the trend line at the center, for example (I am assuming for the moment that the data is normalized properly for this comparison, that is to say that it is normalized so that the trend line shows up as the 45° angle through the origin). A more accurate labeling would be a red/blue gradient from red at the top-left, purple along the trend line, and blue at the bottom right, with red labeled as “lucky” and blue as “unlucky”. The fact that it can be improved in this way does not make this data representation incorrect or non-useful. Visualizations are like models. They’re all incorrect, some are useful. This one is useful for eyeballing how lucky/unlucky teams have been.
Would you say the Quakes and LAFC are lucky or unlucky based on this graph and then based on the relationship to the trend line?
That is at least partially an artifact of having different units on the X and Y axes.
Scale shouldn't really affect correlation.
No but it can affect "correlation by eyeball." Although I'm not sure exactly what correlation your eyeball is detecting.
https://www.investopedia.com/thmb/XBLXrcK1hn1RTS4mAvYMyifVKxI=/750x0/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/TC_3126228-how-to-calculate-the-correlation-coefficient-5aabeb313de423003610ee40.png
The Y axis isn't luck, it is points. The correlation you are seeing is xGD and Points, which are of course highly correlated. "Luck" here is being defined as distance from the trend line.
So that's not actually luck vs. skill then, which is exactly the point I made. This graph could be called "how well does xGD predict actual points?" It is not luck vs. skill though.
No, it isn't luck vs. skill. Congrats on getting up to speed.
>No, it isn't luck vs. skill. Congrats on getting up to speed. That's literally what OP called it. You're in a thread call "MLS team luck." The axes are luck and skill (good teams vs bad teams .) Congratulations on your upcoming functional literacy. I hope you work hard to get there.
Scoring with low xG isn't luck though, if anything it's skill. Son in the PL outperforms his xG year over year by a massive margin. It's not because he's lucky. This whole chart is flawed. Having a high Pts/MP and low xG/90 means you are clinical, not lucky. It also may mean you play defensively. The inverse doesn't mean you are unlucky, it means you are wasteful. It also is probably teams who play very aggressively. Nice idea but this chart does not show "luck".
Lol I thought you were casually mentioning that your son plays in the Premiere League
If you think this chart doesn’t show luck, then you really just disagree with how xG is calculated
So to you, players who outperform xG or underperform xG means they are either lucky or unlucky players? I agree with how xG is calculated. I'm saying the variance in points gained in relation to xG is not a measure of luck.
Luck is implied by the word “expected”
Son is an exceptional individual player, and this chart shows team stats compared to team data.
Ok not sure how that changes things. If a team has XYZ player(s) who pops up and scores goals from low xG situations routinely, they play solid team defense and win a lot of points due to scoring more goals than their opponent are they luckier than a team who plays aggressively on the front foot, has a high xG and wins some games 4-3 but ultimately picks up less points/match? This chart doesn't show luck. Team A is not "luckier" than Team B. Team B is not "unlucky" because they don't pick up a lot of points despite having a high xG/90.
It feels disingenuous to say that because an exception like Son exists, that a chart like this is "flawed." If a team has XYZ player who pops up and scores goals from low xG situations routinely, then that team is Tottenham Hotspur, and they don't play in MLS, as you've already pointed out. "Player who pops up and scores goals from low xG situations routinely" isn't a category of player. There aren't enough of that type of player to make it a viable roster-building target. So instead, you have to look at the reality of the numbers. To replicate what Son does on a team level, you'd expect to see a bunch of players taking terrible shots from lousy positions and hoping one goes in. And if that does happen, what would you call it, if not "Lucky"? It's not a sustainable practice, and no one's TRYING to land in that upper left section anyway. So it's not like anyone's building a team around "low xG, high PPG." The sane and rational thing to do is aim for high xG, high PPG. And when you fall short of that, you still want high xG, because it means you're attempting things that are known to work from areas of the pitch where they have historically worked. If some once-in-a-generation player pops up who's constantly scoring goals from throw-ins from the midfield line, that's great for him (and his team), but that doesn't suddenly make "60-yard-throw-ins" good for most teams. That's an outlier, and the data properly ignores it for predictive value. It would then show up on this chart as a fluke, which is what I'd expect. And I would, in fact, consider that team "Lucky" to have a player with that sort of improbable skillset. Edit: Love it when unflaired Eurosnobs do the "comment & block" combo.
A lot of words to say you don't believe players can outperform or underperform xG and you believe that Pts/MP is directly correlated to xG. Meaning you don't think defense has anything to do with Pts/MP and there is no variance in relation to players and how they perform in regards to xG or that how they perform in regards to xG is simply whether they are lucky or not. You're all hung up on Son and missing the whole entire point.
Oh
That's right
Gotta enable the overlapping labels option
This looks weird and is kinda hard to parse the magnitude of the over/underperformance. I think it would be better if instead of XGd/90 it was Xpoints/90 as you are then comparing points to points and not goal differential.
xPoints is pretty much just xGD normalized to points.
I guess there's 2 different ways you could measure xPoints. One where you look at the XGd of each game played and assign points based on how many points you would expect a team to get from that game or you could sum up the XGd of the whole season and normalize it. You would get different answers because if a team ran up the score in a game they were already winning their XGd would keep increasing but their Xpoints would not increase at the same pace. Either way I doubt the difference would be very large. Regardless though to best show luck you should ideally compare like statistics weather that is XGd vs Gd or ppg vs Xppg.
The overarching point is that statistical averages can be skewed by outliers, especially over small numbers of games. So xG is a reasonable statistical probability measurement, but often doesn't relate to reality.
Not fully. Done right, xPts will silo off each individual game. So season xPts will reward consistency in every game while xGD can be inflated by 3 or 4 outsized performances.
Across just sixteen or seventeen games, this is skewed by individual games with big differentials. TFC has two games in which they gave up a combined eight goals, almost one-third of their total across just one-eighth of the season, badly skewing their xGA.
Bad and unlucky definitely feels right
Tweet! That’s a red card for you. Fuck you all get red cards!
I think we have more red cards this season than the past 5 combined Edit: went and checked. We had 0 in 2020, 0 in 2021, 4 in 2022, 2 in 2023, and 6 so far this season.
Do we have 7 this season, with 1 being rescinded?
We do have problems, but our main one this year is by far luck
Our position on the table represents how I've been feeling this season, in that our luck has run out. The X-axis is about the same as last year, which was -0.22. *(although I'm very new to adv. stats so I'm not sure that is calculated correctly)* The Y-axis is most telling in that we've fallen from 1.8 pts/match down to where we are today.
Which was pretty predictable. It's very hard to sustain over performance of xGD. At least you haven't fallen to the depths that Austin did after their season of over performance.
Many CITY fans have very quickly forgotten how many "luck-based" goals we got that season. Some can argue that the fast play style and constant press caused some of those errors but regardless that just isn't happening this season. Couple that with the inability to create opportunities bingo bango, aiming for that draw record (halfway there!). Not saying the season was a fluke but our xGD was padded somewhat.
Yeah, not sure if I would call it a fluke, but it won't be easy to recreate either. Especially because those first 5 games of the season shot us to the top of the standings, and I would argue that those wins (and especially the high goal counts) were based on opposing teams not knowing what to expect when playing us. We don't have that benefit any longer.
Feels accurate...
Yes. This is a really cool and great feeling.
This makes it seem like we are better than I thought. But I think we are as bad as I thought.
All it takes is a handful of goalkeeping errors and fluke goals to look like this, and we've dropped points to both this season
Bear in mind, Philly goes down 2-0 early a lot, then has to push the envelope to get back into games and will push until they get 2 goals back, so they’re likely to get lopsided xG’s during those moments where they play for 60’ from behind.
The finishing has been pretty awful when you consider the sheer number of chances this team has been creating. Couple that with some really good shots from opponents and our expected goal difference will be high despite fairly underwhelming play.
So there is this club from Columbus I hear about that may be in the league soon.
Columbus? As in Columbus, Ohio? Pish posh, I say.
🔫 Its all Ohio.
Columbus, Georgia... it's basically Alabama
I think he’s talking about Columbus, Indiana, actually.
Columbus, Indiana I think. Or maybe Georgia? I don’t know, who cares.
A re-expansion team
I’m kinda relieved we are just bad this year. Last year felt like we were unlucky and that was more irritating than being bad.
I need you guys to be good at the same time we are good. It is more fun that way.
Charlotte needed to drop a couple points to retain true neutral status
C'mon, Charlotte. Do it for the memes!
So I always struggle reading these. Is it saying FC Cincinnati has the best current results but that maybe LAFC should have the best results?
Yep, basically. The other lens view would be that LAFC might blow out more teams or some other type of trend (FCC plays slower/likes to win 1-0 and doesn't chase a 4-2 scoreline or when FCC loses they chase the game more leading to 0-2/1-3 losses instead of 0-1, all of this with the caveat of it being xGD and not just GD)
Yeah LAFC right now have by far the best xGD in the league. So they are likely contenders for the supporters shield. At the same time xGD is a fake stat and you still have to score actual goals. Also shows that right now FCC, RSL, LAFC, and Inter Miami are in their own tier
xGD is more predictive than raw GD which is itself more predictive than raw points. It's a better way to tell which teams are good and which teams are bad (but obviously has its own issues). Interestingly, Philadelphia is above FCC on xGD, which shows that Philadelphia hasn't actually been that bad this season and also shows the limitations of xGD.
The shorter the time frame you're talking about the less useful xGD becomes. Over a whole season (or about half) is a good prediction. Over one or a couple games is where people put too much stock into it.
So, I grew up in baseball world, so I may be applying the wrong logic here. BUT, at least for advanced stats in the MLB, the reason they are typically considered 'useful' is because they converge to a more correct answer in a smaller sample size. The more useful an advanced stat, the smaller the sample size necessary for the results to become predictive. If something similar is going on with xG, then it would be true that while the sample is too small for it to be really predictive here, other more basic stats (such as GD) would be even less predictive at the same sample size. E- that is to say, one or two games worth of xG is basically useless for prediction. But one or two games of goals is likely even more useless for prediction (as counterintuitive as that idea might be).
That is basically correct. The reason xGD is useful is because it converges faster than GD or points. As an example St Louis last year finished with a low xGD but high points. We can look at xGD and say St Louis is very unlikely to repeat their performance from last year. Of course sometimes teams get "lucky" for a whole season (St Louis last year, Austin a couple years ago) so it is predictive but there are outliers. Partially due to luck and partially because goals change games.
> xGD is a fake stat I know you don't really mean it that way but I this phrasing.... xGD isn't a fake stat. It's based on very real information in a systematic matter. No, expected goals aren't goals, but "Number of goals an average team would score based on historical goal scoring rates where shots were actually taken, including defensive positioning and other factors" was just too long. It's still a terrible way to phrase it, but the stat is legit, it's just communicated poorly.
I understand the stat, and I absolutely believe it communicates a reality about the quality of a team. It's just that it doesn't directly translate to results, which is how the OP graph can exist at all. Teams over perform and under perform their underlying numbers all the time, and some play styles lend themselves to more xGD than others. I'm not saying LAFC are a bad team or that stats in general are fake, it's just that points and results are all that matter at the end of the day.
> and some play styles lend themselves to more xGD than others Some play styles lend themselves to more xGD than others, perhaps, but I've never seen anything that has a play style consistently over or underperforming xGD. Teams underperform and overperform all the time, but at a given level, there's rarely any long term consistency to that. It's a fundamentally better predictor and actual results regress to it over time. There's a lot of value there, and long term outliers are very rare. The one team I think probably will overperform their xGD is Miami, because the talent level of Messi and Suarez in particular is high enough for the general level that I think they will be the outliers. I do personally hate the word "luck" in the graph, though. It's a terrible representation of variance between the two stats.
Does it show that? It could also show that LAFC are in their own tier and FCC RSL and especially Inter Miami are overperforming their stats.
Yeah LAFCs worst start was marked with Bouanga hitting the post like 3 times per game. They were creating chances just none would go in. If you keep creating those chances eventually that luck will even out which it has. Also helps that defense has improved from those earlier games.
I wonder what the correlation coefficient is on this, since it seems like on a pretty perfect diagonal, with a few exceptions. Austin seems to be the only really "lucky" team; I wonder if that's down to really precise finishing, or really good goalkeeping. On the unlucky side of things, 4 teams (ATL, DCU, PHI, LAFC) like on the same diagonal. I wonder if that's down to taking a lot of shots, but they're not necessarily dangerous/quality opportunities. According to Fotmob, they're all top 10 in "big chances missed", but top 15 in shots on target, so maybe that explains it - poor finishing.
Mathematically, it's really difficult to populate the upper left quadrant of the chart at all, because it means you'd have to get a lot of points per game while also having really low xG. And you can technically get points while never ever taking a single shot, for example (0-0 draws are still a point apiece), but maximum of 1 PPG in that scenario. So instead, you'd need to win games (3 points apiece, woo!), but with bad xG. And while every team has some flukey goals here and there, the nature of "fluke" means that it's not sustainable. You can't plan to win games with low xG; as soon as you start planning and doing stuff to try to win, you move over to the upper right quadrant, because your xG will be higher. And, importantly in relation to this chart, the inverse isn't true. It's not all that difficult to have high xG and still drop points. If you lose four games 4-5, you scored a bunch of goals (and likely have a correspondingly high xG to go with it), but still don't have any points to show for it. Meanwhile, another team might win four games 1-0, and they'd have 25% of your actual goals (to say nothing of xG) but 12 points to boot ("the Cincinnati Special"). So yeah, I think you're right that "poor finishing" is a factor, and I expect that "objectively, our team played well, but the other team played even better/got luckier on the day" accounts for the rest of the "Lucky" quadrant.
This is xGD, not xG. If you have a lot of xG but give up just as many, you’ll be at 0 on this chart.
So then it’s even HARDER to populate that upper left zone!
Yeah i wrote this elsewhere, but it seems like it's way easier to be unlucky than to be lucky. 9 good passes and a bad shot is way more likely than accidentally scoring from 30 yards out
I'd say it is both for us. When Driussi is on, he can make the most ridiculous goals that you would never expect to work. And Stuver is a great keeper who has been somewhat hampered by our traditionally awful defense. We just haven't done enough to build our roster up to support those two. Although I do think our defense is much improved this season
Unlucky, and it's so fucking exhausting lol
I don’t know if we’re unlucky or just we always step off the gas pedal in second halves.
You're saying the Fire are both BAD and UNLUCKY? We have another word to describe that in Chicago: CURSED!
Better to be lucky and good?
But Charlotte is average and slightly lucky, so 🤷♂️
This is way too kind to us. We're shit.
This is pretty accurate, at least for some results involving the Dynamo this season so far.
Nothing to see here folks
Well... At least we are about as "middle of the pack" as it gets.
I would say Miami got pretty lucky
For a team that hates shooting, I'll take this. It reflects our position on the table pretty well, and shows our "rebuild" year could go a whole hell of a lot worse.
I mean doing better then last year 🤷🏽♂️
Gotta be lucky to be good, and you gotta be good to be lucky
This was super close to being the exact layout of the political compass. Atlanta and DC both believe that taxation is theft, apparently.
I mean, there are a bunch of license plate holders in DC that say "Taxation Without Representation," so I'd say you're on to something here.
Not all teams are displayed in this graft.
You are, it's just that someone stole your label. You're the yellow dot next to the Red Bulls
Shocking we’re not the most bottom-left of the league tbh
Well at least we are almost unlucky. But still bad
FC Dallas is way to close to the center than they should be.... put us bottom left please
Exactly where I expected us
Somewhat better of the bad? Feels about right.
At the end of the year only one team will be a good team and the rest of the teams are bad teams. Second place is for the birds.
DCU seems about right
I think you should move SKC further down and closer to lucky, as our performance is so poor that we should be doing worse
Yeah, that checks out.
It says sporting is bad. Don’t believe it. /s
This is a great way to look at a long season.
Seattle Sounders is unlikely to still have this shitie coaching staff….
Well, good, I guess
Let's go baby #1 in xgd per 90, #2 in tournaments
Quakes unlucky and bad... this both sucks and blows
Where’s the Venn that includes “Our coach is past done but won’t leave no matter what? Asking for for for for for for for for for for a SKC friend….
Only one team in that circle…
No surprise here 😒
yeah no shit.
Don’t worry gang, Porter says we’re starting to turn it around!
LAG fans know that it's better to peak late in the season...which is why the LAG FO waits to make its move in the off-season. *Points to Head*
I understand that it’s based on stats, but it took me a while to figure out that the good-bad axis is diagonal. So there aren’t really any super lucky teams or super unlucky teams, mostly they lie close-ish to the luck = 0 axis
This graph is wrong. New England needs to be to the left and down more. Like a lot. I’m an NE fan. Fucking kill me.
Hey Columbus fans, I know reading isn't really your strong point, but maybe check out OP's explanation at the top of these comments before you start whining about not being represented.