Thanks for your views, it was interesting.
Kafkaesque wrote: ↑Thu Jan 04, 2018 12:22 am
A quick check of number of goals by each team in PL this season for 0, 1, 2, 3, 4+ respectively is 32, 30, 21, 9 and 8 % with similar numbers last season, so lumbing 0-4 goals together as what teams score is a bit simplified imo.
I just mean't that the normal range of goals was between 0 and 4, obviously not that each outcome was equally likely.
32% + 30% + 21% + 9% + 8% = ?
Kafkaesque wrote: ↑Thu Jan 04, 2018 12:22 am
I don't know where you're "a dozen matches" from?
It's starting to look like xG isn't as complex as I thought, the reason I'd referred to the stats over a dozen games was that I thought expectation was calculated for each player in context, not that it was an average over hundereds of random players and games.
Kafkaesque wrote: ↑Thu Jan 04, 2018 12:22 am
One of the reasons xG came to was that someone realized that there's very little difference between the outcome based on who takes the shot.
That's the killer one that's hard to believe and impossible to prove.
Do you have the stats on the personal xGs of all the strikers in the the PL for this season? I'd love to know what their xG varience is from this mythical Standardo Generico fella who's played in 10,000 games.
I get that top flight players are all of a high standard and probably don't deviate from the average
that much, but if one guy is worth £75m and the guy next to him is worth £40m, somebody thinks that very small difference is worth having. Maybe it's just 2 or 3 extra goals from a 100 opportunities, but depending when they occur that could win a championship or serious spoil a 'system'. And that variation exists in every team.
I do accept though that this arguement doesn't prove a link between value and conversion rate as his additional value might be in other less direct ways, tackle success, pass completion, leadership or many others etc.
Kafkaesque wrote: ↑Thu Jan 04, 2018 12:22 am
Incidently, given that you're a trader in the NBA, you might be interested to know that NBA teams are to varying degrees using a Basket version of xG.
It's interesting you say that because I've been looking at basketball from this angle since I heard about xG in football.
The original premise being that,
-If only 3 in 10,000 are drafted into the NBA then surely they must all be within a gnats whisker of each other.
-With only 5 on the court not 11 the variables are massively reduced.
-Players have many more games/shots/goals so you can obtain a better sample without going back years
-In basketball where you're pretty much either assisting or shooting rather than being generally being more unqualifiably 'useful'
-No goalie
-Smaller playing area
-Only 30 teams in the whole country
...and one or two others, a piece of cake compared to football so it seems?
So far I've found almost nothing in data or on the net. Different players deviate from the norm enough to make a significant difference to the outcome. Again justifying certain players being worth a lot more. You've only got to look at free-shots, a man, a basket, no goalie or even surface, 100's taken in a season. Certain players outperform others week in week out.
Now I admit I'm a million miles from being a statistician but when you say this....
Kafkaesque wrote: ↑Thu Jan 04, 2018 12:22 am
My understanding is that a lot of teams have toned it down from being the whole foundation of their set-up,
....then it's probably something I won't find if the entire might of NBA are downgrading it's importance. And basketball is much much more simple than football.
Kafkaesque wrote: ↑Thu Jan 04, 2018 12:22 am
And someone like James Harden has spots, where he'll never ever take a shot from because the xG is poor.
No way, James Harden has spots where he'll never ever take a shot from because
his xG is poor. Basketball has so few variables, not even weather, that players know their strong areas from taking 1000s of sample shots in practice. Different players have different throwing styles and faults that make certain angles more appealing. They don't just shoot from where the nationwide hotspot is.
If this general notion of 'average' xG was poor, nobody would shoot from those spots, not just Harden.
Kafkaesque wrote: ↑Thu Jan 04, 2018 12:22 am
Most prominently in how the numbers of 3-pointers have risen dramatically.
The are factors other than guessing xB caused that change.
The rise in 3-pointers is partly driven by the success of teams who's coaches have favoured 3-point attempts. Favouring 2-point or 3-point attempts makes little statistical difference (again or they'd all play the same way) There's also a case of crap teams trying to copy the style of the big boys, but the big boys favour 3s because they have the guys who can score them. The gameflow psychology is different too with bigger swings and coaching styles go in and out of fashion.
There's also issues around how refereeing has changed slightly, more offensive fouls, less defensive ones, which has made short 2s less appealing, and if you're going to try long 2s, it might as well be a 3.
I can't back that up because I only heard it in commentary and can't easy find the stats to confirm it.
..sorry all for writting such a stupidly huge message and straying off football, but I think the parallels with basketball xB are worth consideration.
Is anyone looking at darts or snooker from this angle? I don't follow them so I don't know.
Football seems the most complicated sport you could ever apply it to, has it been proven in the much more simple sports?