Welcome to Wolves Ruben Neves

[Alan]

People look at Moneyball as "this is how it can be done everywhere" whilst forgetting that baseball, love it or hate it, is a really static sport, especially relative to the likes of football, rugby, hockey, basketball, etc (games where there are not consistent and regular stoppages in play, basically). This makes actions and expected values therein much easier to track and parse in baseball versus the aforementioned sports.

That model worked very well for baseball (at least for a time), but rather than adjust expectations for the outcome (ie, change the model), these new age football "statisticians" seem to want to force the baseball model onto football. Which doesn't work for a variety of reasons that are obvious from the outside but easy to hide from within a culture (groupthink, yes men, etc).

 

[Alan]

xG is so crude a measure. Shots compared to a particular position on the pitch in comparison to every other shot taken from that position leaves out so many variables it's almost worthless.

xA is the better of the two but at the moment is presented badly.

If presented in categories of xA (set pieces, open play, transition, errors (forced and unforced)etc) it would be so much more useful to everybody. As it's presented in its most broad terms it's a bit like xG, a bit useless.

As with every other stat in every other walk of life, context is everything.

There was an interview on Martin Lewis's podcast with Bill James last year. James has retired as he's fed up with stats being used incorrectly, mainly for confirmation bias.

For your consideration:

Stats Perform’s xG model is built using a logistic regression model that is powered by hundreds of thousands of shots from our historical Opta data and incorporates a number of variables that affect the likelihood of a goal being scored, some of the most important of which are listed below:

• Distance to the goal
• Angle to the goal
• One-on-one
• Big chance
• Body part (e.g., header or foot)
• Type of assist (e.g., through ball, cross, pull-back etc)
• Pattern of play (e.g., open play, fast break, direct free kick, corner kick, throw-in etc)

We recognise that some situations are particularly unique and so these are modelled independently. Penalties are given a constant value corresponding to their overall conversion rate (0.79 xG); direct free kicks have their own model; and headed chances are valued differently for set-pieces and open play.

The above isn't meant to persuade you one way or the other, just some good context for the conversation.

 

[YoungWolf]

Statsbomb are really good with xG now, so many factors (even including the height of the ball, position of GK) added in. Like Dans says, long term it's a good measure. Although quite often hard when teams change manager so often!

Anyone solely going off stats or solely going off the 'eyetest' for player recruitment would be very stupid as we already seem to have agreed

 

[Alan]

Statsbomb are really good with xG now, so many factors (even including the height of the ball, position of GK) added in. Like Dans says, long term it's a good measure. Although quite often hard when teams change manager so often!

Anyone solely going off stats or solely going off the 'eyetest' for player recruitment would be very stupid as we already seem to have agreed

Plagiarizing more to build on the above...

The main criticisms of expected goals (xG) often appear in scenarios where the metric isn’t actually being applied correctly. The most common of which is at the game level. The team that has the higher xG in a match doesn’t necessarily imply that they should’ve won the game. xG is only measuring chance quality and not the expected outcome of the game. Exactly as the old saying suggests, goals do change games and the score line influences how teams play. If a team takes an early lead, they don’t necessarily ‘need’ to generate more chances and we often expect to see the opposition generate more goal scoring opportunities for the remainder of the game in pursuit of a comeback.

Another misconception is in the literal interpretation of the metric name. We do not “expect” goals to occur exactly as the likelihood predicts. We also understand that fractions of goals cannot be scored. The name “expected goals” is derived from the mathematical concept of “expected value” and it is a measure of the likelihood of an outcome occurring. The expected value of a fair coin toss is 50% likely to land on heads and 50% likely to land on tails (the expected heads or the expected tails is 0.5). We do not expect exactly half of our tosses to land on each outcome, but rather that over a larger number of coin tosses, it is likely to regress to this balance. The same applies to expected goals. Variance from the expected value is inevitable and this is valuable information that we can analyse in football.

A player or team who has been overperforming their xG, does not then have to underperform to regress to expectation. This is a concept known as the Gambler’s Fallacy. While we would expect them to regress back to scoring in line with their expectation with their future shots, they have already ‘banked’ this overperformance and so we will still expect them to overperform by this amount in the season aggregates. In the same way, if a coin toss landed on heads ten times in a row, future coin tosses are still equally likely to land on heads as they are tails, but the ten times that the coin landed on heads have already happened.

I generally feel that the people really doing the work on producing these statistics are pretty aware of the sorts of criticisms someone like Johnny may level at them and are doing their best to counteract those flaws.

 

[Mel Evo]

I’ve always thought that the richness of stats in baseball is driven by the lack of depth elsewhere in the game, there being so few variables compared to other sports. It’s a limited game so let’s go nuts on the stats. I should add that I do want to like baseball, and will still happily watch it in a bar or if I have nothing else to do. Also, the eyeball test is made trickier by the optics of it just being a load of fat blokes in PJs swinging a stick and missing.

 

[Tony Towner]

If we went down the Moneyball route Jeff would employ Jonah Hill

 

[WsWolf]

For your consideration:

The above isn't meant to persuade you one way or the other, just some good context for the conversation.

Doesn't take into account the player. Haaland and Leon Clarke shooting from the same scenario would have the same xG. I can't get behind any metric where that is the case.

 

[Alan]

If we went down the Moneyball route Jeff would employ Jonah Hill

I'd hire Hill before Sellars tbqfh

 

[Alan]

Doesn't take into account the player. Haaland and Leon Clarke shooting from the same scenario would have the same xG. I can't get behind any metric where that is the case.

That's a very interesting point. I wonder if ways of controlling for that are being looked at.

Possible the argument would be that xG is more about everything up to the finish. Which likely is a conclusion that won't work for everyone (but shit, man, what conclusion about anything works for everyone).

 

[WsWolf]

That's a very interesting point. I wonder if ways of controlling for that are being looked at.

Possible the argument would be that xG is more about everything up to the finish. Which likely is a conclusion that won't work for everyone (but shit, man, what conclusion about anything works for everyone).

They don't even do simple things like putting a multiplier on a striker Vs a centre half for example, that should be pretty basic.

 

[Johnny75]

That's a very interesting point. I wonder if ways of controlling for that are being looked at.

Possible the argument would be that xG is more about everything up to the finish. Which likely is a conclusion that won't work for everyone (but shit, man, what conclusion about anything works for everyone).

And that's the issue.

As has been raised the quality of striker and their size/ ability is the defining factor which isn't included in xG but then you would expect a good player to out perform the xG number and a bad one not to.

It's certainly an interesting argument either way and clearly there is a place got stats.

 

[Johnny75]

Statsbomb are really good with xG now, so many factors (even including the height of the ball, position of GK) added in. Like Dans says, long term it's a good measure. Although quite often hard when teams change manager so often!

Anyone solely going off stats or solely going off the 'eyetest' for player recruitment would be very stupid as we already seem to have agreed

Statsbomb's spider diagrams are very good, sadly not given enough attention in the media as these are genuine metrics people could compare players and tactics with.

 

[Alan]

Statsbomb's spider diagrams are very good, sadly not given enough attention in the media as these are genuine metrics people could compare players and tactics with.

You know any real statistical analysis will make people's eyes glaze over.

Gotta put up the numbers that sell, ay?

 

[WsWolf]

Statsbomb's spider diagrams are very good, sadly not given enough attention in the media as these are genuine metrics people could compare players and tactics with.

They are but a personal irritation is when journalists (yes you tim Spiers) use the charts incorrectly.

 

[Alan]

Makes me sad, too, @Johnny75. You know I love me some numbers and percentages.

Anywho. Didn't mean to hijack the thread quite this badly.

 

[Tredman]

You know any real statistical analysis will make people's eyes glaze over.

Gotta put up the numbers that sell, ay?

Poor visualisation if it does.

 

[Lycan]

Tchau Rúben. It's been emotional.

 

[loppers86]

true legend. feels like au revoir to me

 

[Tyrannosaurus Dan]

While I’m pleased we are getting a good fee for him, it’s a shame he’ll be wasting his talents over there rather than playing Champions League football. I thought he’d leave us for footballing reasons rather than financial reasons.

Thanks for the many, many memories, Ruben. The last of the Nuno golden era

 

[Tredman]

Fair to say you don’t know what you’ve got until it’s gone. Without doubt the period up to Luiz nearly killing Raul was the best period of my Wolves supporting life. Not sure I’ll see the same again.