More on Chelsea's woes

More quick thoughts on the Chelsea situation:

The issue of how anyone could have predicted Chelsea's decline has been a prominent thought recently.  I recall about March time having a eureka moment with regard last year's Chelsea team when I realised that much like Man Utd 12-13 or Liverpool and Arsenal 13-14, on balance, "things were going their way" and by that I mean they were collecting points at a rate above and beyond an expectation derived from versions of their shooting stats.

Following on from James Grayson's work in building a team rating- so beyond simple shot numbers- I tracked similar myself and found that for 2014-15 two teams overachieved at a far higher rate than anyone else: Chelsea and Swansea.  You would find similar using xG.

So Chelsea's true talent level was a good deal less than the 87 points they put together.  Their season existed in two clear halves; in the first 19 games they recorded solid top 2/3 numbers yet picked up more points than any other team in the last 6 seasons (46) and in the second half they picked up 41 points whilst putting up second tier numbers.  In the first half, their defense was exceptional at preventing chances and also goals.  In the second half, their defense was less effective in itself but their save percentage rode high.

I mention this because there is a reasonably wide assumption that despite this season's malaise, Chelsea will improve.  And a bit of debate has centred around whether they well be able to qualify for the top four or failing that, show top four level form for the rest of the season.

I would contend that throughout early to mid 2015, Chelsea's underlying form has pegged them as a 5th to 8th team, therefore, if they are to revert to the form which might be expected of them based on last season's most recent 19 game form, it's reasonable to assume that their true level is just that: a fifth to eighth level team.  Shot ratios around 55-58% will most times find a team exactly there: in the Europa mix.  That kind of level can expect a broad return of 40-50 points from here on in, which would lead to a full return of 51-61 points.

Surely too low?

Well, Omar Chaudhuri's been tracking Sporting Index' points predictions from the start of the year and they now have Chelsea at 63 points, down from a starting point of 83:

So the bookies, who let's remember are professionally and financially deigned to be more right than I am about these things, feel that Chelsea can recover, to a degree but not to an extent that 4th place is viable. A projection of 52 points in 27 games is ~4th place form but achieving 4th place on top of 11 points in 11 games is likely beyond reach.

What this also shows us is how reluctant even the bookmakers were to downgrade Chelsea's 14-15 season.  Projecting them on 83 points- the same as City to start- wasn't unrealistic.  While I felt City were strongest set for this year, in my preview, I was certain that Chelsea would be tough to surpass, indeed I suggested that any team that scored more points than them would win the title.

In the range of media pre-season predictions I saw, there were a few crackpot suggestions that Man City would struggle, but I don't recall anyone picking Chelsea to fail and you would have been certified if you had predicted them to be picking up points at relegation pace into November.

So while there was a case to be made that by now Chelsea could have been predicted to be pulling in points at under two per game and thus sitting 4th to 6th, nobody could have predicted that they would have cracked to this degree.  At best I can project that they could be on 14 points by now, only a win ahead of their real total.  This is how bad they have been.  On the pitch, this isn't a case of "luck" or unaccountable variables intervening.

The other thing that could not be predicted was the complete porousness of their defense.  While seemingly tiring as 2014-15 wore on, the tactical shift in the team was built on a sturdy defense, when I tried to analyse their back four, each of them appeared to be producing numbers akin to centre backs; Mourinho's block was in full effect.  So if you were theorising that Chelsea were unlikely to perform at a high level this year- something very few did- it was entirely logical to presume that any suffering would be on the front end, to follow on from the narrow victories and uninspiring shot numbers of late season. And Mourinho has simply never had charge of a defensively suspect team.

To predict that this team would suddenly be conceding two goals a game and only Sunderland would be conceding more shots on target? Nah, that's just crazy talk...

So then you start to wonder about their transfers. Why is De Bruyne ripping up the league at a different team? Why are the first change strikers Falcao and Remy and not Lukaku? What happened to Cuadrado and Salah?  Beyond Matic, Fabregas and Costa, Chelsea's transfers are far more erratic than we have become used to.

And did this overachievement last season mask true decline and the end of a team? If Terry is in decline and none of his partners are up to his standard, whilst Ivanovic is regularly flayed out on his flank, Fabregas has high miles, Hazard has played relentlessly for a number of years... 

No new blood and then the chaos of potential distrust following on from the Carneiro incident.

It's multi-faceted.  And without access to the day to day operations of the first team, it's impossible to do more than speculate as to what the human factors are. And those factors must be real, for Chelsea to have fallen so far outside predictable parameters, further inputs beyond those that can be modelled effectively must have had an impact.

I tweeted earlier that it reminded me of post Ferguson Man Utd, but in that case Ferguson was long gone and the problems he left were somebody else's issue.  Here at Chelsea, and maybe beyond the cost of his dismissal, this is why Mourinho remains: there is a big task at hand.  A lot needs to be achieved- the squad suddenly looks in dire need of new blood and it will take more than one window to solve this. 

Anyway...

After I posted this @tommillard replied and pointed out the BBC predictions table. No slight on their skills but only one picked Chelsea outside the top 2:

And Tom also pointed out the one guy who was down on Chelsea pre-season, Mike Holden

Have a look at his preview here

On PDO

Once more the topic of PDO in football has risen to be debated among the analytics Twitterati; opinion has been kicking around for a few days and the Analytics FC podcast chatted around the topic too. I got a mention as someone who uses PDO in analysis, which amused me as generally, but not exclusively, I consciously try to avoid using it in writing. 

No matter, i'm well aware of the issues with the metric but slightly mystified as to the strength of anti-opinion it still generates.  Nobody is claiming PDO as a top line metric, as James Grayson has shown regularly, it does not habitually repeat and regresses over time.  What it does do is give a useful one hit overview of a metrics that a team has little to no functional control over.  Precisely because it oscillates around a fixed point gives it a degree of simple understanding.

As I write West Ham have a PDO of 122 which is high and incredibly unlikely to sustain.  Similarly Southampton and Liverpool have PDOs at 78 and 81, which are equally low and equally unlikely to sustain.  What does this tell us? Via one number we have an instant method of cutting through the overlying narrative that a team is good or bad; we can see whether a team is running hot or cold.  For this reason, some of the strengths of the metric as an informer lie around its ability to define reasonably short periods of time. 

At its extremes we find teams that are interesting and it offers us a route in for for further analysis.  Having highlighted West Ham via their extreme PDO, I can then quickly zoom in on the factors that are contributing.  Their save percentage is slightly high, but not too extreme (74%) but the rate in which their on target shots are being converted is huge (49%) and simply will not continue at that level long term.  Then we can look at shot levels and be less than impressed, or their wider all shot conversion and ponder that either their finishing talent is akin to Barcelona or it's a freak run. 

Liverpool are dying at both ends, Southampton's problems are all in the save percentage.  We spot this with a one hit metric, then we look deeper for further issues.  Are these teams spending a lot of time in deficit or ahead? Are they crippled by injuries to key players? What is going on?

Nobody conducts in depth analysis using PDO alone, like any metric, in isolation it has limited use.  Its components are far more useful as part of a chain of metrics that inform on different aspects of a team's qualities.  Chief among the chain will likely be a version of a shot metric be it simple or an iteration of expected goals and more and more we seem to be moving towards ideas around zones. 

A by-product of all this is as complexity increases and standardisation remains tantalisingly out of reach, there is still value in metrics derived from actual events.  With reticence still prominent in many aspects of football-- from clubs to media to fans-- there is a small duty among analytics proponents to maintain a degree of accessibility and understanding.  With many people focusing on a move towards club work, it is worth noting that recommendations for the forthcoming Optapro forum have placed an emphasis on relevance and applicability and we've certainly not reached a point where rejection of simply derived metrics benefits the whole.

And how do you replace a simple concept?

A kind of plus-minus expected goal figure is hindered by the aforementioned issue of non-standardisation and complexity of derivation and even in usage largely highlights the very same teams as a basic PDO calculation. Anyway the factors involved here are not fixed measurements of a team's quality.  Like a recipe, relevant ingredients come in different quantities yet combined can create the right mix.  For too long too much focus has been put on issues with this metric, be it the mysterious name or non-intuitive meshing of non-related aspects, and missed its simple strength; as a simple temperature gauge for a team's performance.

That's all it really does, and all it needs to.

Time to move on.

Analytics for the People

Richard Whittall has recently written an excellent column for 21st Club in which he explores the gap between analytics and its functional implementation with football clubs.  He finishes up with this: 
 
The current field in football analytics is very good at many things, but not so good sometimes in identifying specific problems for which analysts may provide a partial or whole solution. Work on the latter will help further bridge the gap between analyst and club. Sometimes, it’s important for analysts to step out of R and Tableau and start to breakdown if and how clubs can actually move the needle on some of these predictive metrics. Otherwise, they are like doctors who are only able to offer a diagnosis, but not a cure. 

Wise words and certainly advice that should be heeded if you are one of the many people in the market offering analytic solutions for football clubs.   With such work being necessarily proprietary and the retention of a competitive edge encouraging secrecy from within clubs, it is not always obvious how analytically switched on the industry is.   Leading data providers such as Opta and Prozone occasionally offer a window into the products they offer to clubs, in particular recent Prozone videos from Hector Ruiz and Paul Power showed great skill and clarity alongside the benefits and economies of scale afforded by full data access and a dedicated and skilful workforce.  One presumes that by this point most clubs will have at least a small analytics department and probably a lot more.  Whether such a department is fully integrated with coaching or the first team will likely vary on a club to club basis, but the point remains: analytics does not exist in a bubble, it is in place, there are professional companies that can offer a full package and access to the market from the outside is difficult.  Plenty of people want to work in football and whilst smart in principle, co-opting a few models from other industries and creating a brand is unlikely to improve on what is already available.  But, and I feel this is important, a desire to work in football is not the only reason people are interested in or learning about analytics.

Indeed, none of this has stopped a vibrant online amateur community from sprouting up in recent years.  The advent of data sites such as Whoscored and Squawka has offered easy access to data at a level that far exceeds what was available prior.  Now, anyone with curiosity can collate data from numerous competitions at a player and team level and play with it.  It can be analysed and truths, both whole or partial, can be uncovered.  These truths have a variable application.  For some, with good technical skills, predictive modelling can inform betting, for others fantasy football.  I choose to tell stories about what I've deduced and i've sunk many hundreds of hours into it because I find it interesting and intellectually rewarding.  As with any subject, there is a learning curve that never ends, not everything I do hits the mark and there are few short cuts to knowledge, but as others who've done this before me have noted, you do it because it's fun.

The current situation in analytics has created different viewpoints.  Firstly there is a great drive for predictability, repeatability and application.  These are entirely logical and commendable aims, but the arms race to maximise these effects has lead to a shroud being laid over the details involved.  In particular, and with one notable exception from Michael Caley, the multiple black box Expected Goals models and advanced derivatives regularly cited have obfuscated analysis due to their non-standardisation.  This is not criticism of any specific model, many hours of hard work and theoretical analysis will have gone into each by people with far more advanced skills than myself and those with such access have doubtless found multiple utilities for insight gained.  My concerns lie around accessibility and interpretation and this is where I feel some parts of the analytics community have missed the point.  

Barriers to entry may have reduced over time, but barriers to understanding have not.  There is no such thing as an "Expected Goal", it is entirely theoretical.  A layman interested in football statistics may not yet understand the value of a shot or a shot on target yet he is quickly encountering hypothetical versions of the things he does understand: goals.  That is a tough sell.  Shot counts are real and easily understandable, they aren't "outdated" metrics, they are the building blocks of all that comes after and if the analytics community has any interest in popularising it's method of thinking and transcending a niche corner of football, the stories told by our fundamental metrics are intrinsic.

And there are many stories to be told.  Variance in league seasons of 34 to 46 games is huge.  Half and whole seasons can go by where the measurable statistical reality of a team is skewed vastly in either direction.  Liverpool's huge overachievement of 2013-14 followed by an almost inevitable regression this season, just one obvious case.  It isn't just the board that need to understand the wider implication of such matters, the fans can benefit too.  Interpretations may differ but we can pull apart possible reasons in the numbers and disseminate the knowledge.  Oh for a day where the average pre-game conversation involves an understanding that a team's save percentage has been unsustainably high or a striker gets cheers rather than murmurs or abuse because fans understand he's been unfortunate rather than inept.

It's probably a long way off but as each year passes, we collect more data and we can test more outcomes.  Our knowledge can grow and with it our expertise and ability to inform.  It is important to encourage people new to the movement and support their effort.  We may strive for professionalism but we all start as amateurs.  Guide rather than chastise and realise that the more people that are interested in football statistics and analytics, the greater the likelihood of resulting success for everyone, whatever your desired end-game. 

This may seem somewhat utopian, but elitism will get us nowhere, accessibility and inclusiveness just might.

A few EPL shooting graphs

Messing about with the 'detailed' tab on Whoscored can be quite interesting and that you can separate out details into 15 minute segments of games allows us to look at rates for different parts of a game.  What do teams do and when do they do it?  I'll present these generally as informative with a little light analysis where I feel something is relevant but having looked at it, I've not the time to make much more of it, so take what you can.

Shots by time period

• Injury time an obvious factor
• Desperation?

Shot type by 15 minute game period

• Early shots more speculative?  We've all seen a player hit a 30 yard 'sighter' early on.
• Blocked results not intuitive here? I might have expected them to rise later on.

Percentage of shots in each half

•  Every team takes more shots in the second half than the first half.

Percentage of shots in first 30 minutes

Who tries to start fast?

Percentage of shots in last 30 minutes
 
Kitchen sink time at Loftus Road?
Anfield roar?
Fergie, sorry, Van Gaal time?

• Villa tail off horribly as the game goes on.  Something Sherwood will need to target. Fitness?
  

On target related to blocked shots

I've got a loose working theory that a blocked shot can be attributed to some degree to poor choice from the player, at least over large samples.  In contrast, 'on target' shots have been shown at team level to be of high value, repeatable and predictive.  Somewhat closer to a blocked shot in terms of value would be an 'off target' shot, I imagine a high degree of variance in 'value' dependent on how far off target the shot is.  Anyway just thoughts, but from this, I posit that a team that finds a low percentage of its shots blocked may be taking 'smart' shots.  It may be refusing a poor value, likely-blocked shot and continuing to keep possession, only shooting when sufficient space becomes available.   So we have a simple measure, the difference in percentage points between a team's rate of 'on target' (smart) shots and 'blocked' (stupid) shots.

• It's is pleasing that the prescriptive football of Van Gaal, Koeman and Mourinho is represented at the top.
• It is also pleasing that the 'run around a bit' football of Redknapp is represented at the bottom.

So just a quick post, bit of food for thought?

Cheers!

Thanks for reading!

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I've got an article on '"Arsenal, Score Effects and a Season Of Two Halves" up at Statsbomb, give it a whirl!
The weekly column resides over there now too.

Thoughts on PDO

I'm going to presume if you're here that you know a bit about PDO

*cue sage nodding*

or at least what it stands for.

*silence*

The @espnmag analytics issue (incorrectly) explains that PDO stands for Percentage Driven Output.
— Matt Cane (@Cane_Matt) February 19, 2015

It doesn't stand for anything, but we'll not get hung up on that.  That's the NHL's job, for now.  James Grayson popularised its use in football (indeed, his treasure trove blog houses 57 articles on the subject, if you're not up to speed spend a weekend over there!) and it is a very useful tool that helps describe teams that appear to be over or underachieving in relation to some of their underlying numbers.   

For example, since losing to Man City and only recording one defeat in 15 games since, Man Utd have had a giddily high PDO rating; a clear example of a team that is overperforming against reasonable expectation.  Arsenal have put up solid shot numbers, certainly better than last season, when high PDO kicked them nominally into title contention.  Later it cooled a little, they dropped off and found their way back to 4th, a more accurate reflection.  This year their PDO has been in the bin and they're two points behind Utd despite projecting to be much better, and are down in amongst the CL pack.

More examples? West Ham have spent the whole season with a high PDO, as have Swansea.  They look to be having good years.  Moreso than say Newcastle or Stoke, who are both generating a low figure.  I suspect the general skill level of these four teams to be broadly similar (In fact a model i've built ranks Stoke 9th, Newcastle 10th, West Ham 11th and Swansea 14th) and the divergence from baseline numbers can at least be partially explained by PDO variance.

So what we have is a good storytelling aid which I find interesting and good fun.

"But the table doesn't lie"

*grits teeth*

No, but it doesn't reveal all it's truths either...

Despite generally liking PDO (and in amongst the stats community not everyone does) I do have issues with its current construction.  Because it has been ported straight over from hockey, parts of it's derivation have been left unquestioned and I think there are a couple of subtle tweaks which may enhance general understanding.  You say tomato, I say tomato.  Hmm... doesn't work so well on paper.
Never mind.

As it stands PDO is:

(goals for divided by shots on target for) plus (saves divided by shots on target against)

AKA

(shooting%) plus (save%)

...then you get a grey area where some people multiply the derived figure by 1000, some by 100 or others, well, me at least, leave it as a decimal. 

Immediately in the definition and the creation of the number, we have a couple of issues.

• Why are we adding entirely different aspects together? (shooting% and save%)
• Why isn't there a standardised numerical format?

I asked Ben Pugsley, because he knows a ton more than I do: "Why is it rated to 100? Or 1000?" and he said that it was a "long held thing in analytics (...) from baseball (...) 100 is defined as an "average" " and that the usage of 1000 was purely a method to add detail and see 4 digits.

So we have elements of "this is the way it's done because this is the way it's always been done."
That's not intrinsically bad, but to me we have these figures orbiting around seemingly meaningless totals:

"PDO is 102!"
"One hundred and two whats?"

"Man Utd are at 1120!"
"I'll fit my brunch in beforehand."

Can anything be done simplify matters?

I am presuming there was a comfort found in adding your team's shooting percentage to it's save percentage; you have built a single figure for your team and you are defining what your team is doing but I feel there is more clarity in the entirely related but subtly different:

"What is my team doing and what is the opposition doing against us?"

I propose this, and I propose it with goodwill but little expectation:

(goals for divided by shots on target for) minus (goals against divided by shots on target against)

AKA:

(shooting % For) minus (shooting% Against)

This does two things:

• We are no longer orbiting around an arbitrary number, we are centering around positive or negative.  A high PDO will be positive and a low PDO will be negative.  Understanding is relatable here, we have the universal law of goal difference: positive is good, negative is bad.  It makes sense.
• We are combining the For and Against aspect of the same metric.  Just as we subtract Goals Against from Goals For to create Goal Difference, we do the same to create PDO or "Shooting% difference".

And it is entirely related why? The eagle-eyed will have noticed, we've essentially derived the same number as PDO, we've just decluttered it a bit.  The PDO of 107 or 1070 is now defined as 0.07.  A PDO of 982 is now -0.18.  Average is zero.

"We are neither positive or negative! We perform exactly as you might suspect! We are a zero team!"

I'd recommend leaving it as a two digit decimal.  In football, PDO variance rarely requires the precision for further digits that hockey desired.  A decimal is also, and again we're basing things on simple logic, the number derived from the calculation.  No further work is required.

There is plenty of work to be done to cross-over many of the metrics used in analytics and there is great complexity in a lot of the modelling that goes on.  Such work is invaluable and important but often lives in a realm beyond average understanding.  In order to attempt bridge the gaps between scepticism and reticence and understanding and adoption, existing metrics need to offer as much clarity as possible and hopefully i've shown that there are methods that can increase this without the need for structural change. 

Thanks for reading!

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Nowadays, you will find my weekly Premier League Round-up over on STATSBOMB and assorted player and team articles as and when I get round to them.  This was initially supposed to be a quick 500 word idea, but i've doubled that and being a bit speculative, I thought i'd put it back here on the rickety old blog.  Plus I know (two or three) people miss reading articles on a pink background (mobile only!) so it's one for the veteran visitors.

I'd like to thank my family, the cat and Acer computers for providing support and er...  a computer in exchange for money.  Until next time.
 

***Transfer news***

****IMPORTANT ANNOUNCEMENT****

'The Big Ripple' would like to announce the transfer of the weekly round-up column to the larger Statsbomb franchise.  We felt unable to turn down the offer made by franchise owner Ted Knutson and as such 'The Big Ripple' would like to extend thanks for your support since it's inception a little over 10 months ago and promises to return with further content as and when it thinks of things.

The column will remain as prior with the same blend of stats, mild humour and Tottenham sections (but not when they've just lost to Crystal Palace and Alan Bloody Pardew) and will hopefully be available from early on a Monday morning.

It is hoped that this transfer will be more akin to Alexis Sanchez than Fernando Torres.

So: Monday morning, here:

http://statsbomb.com/

Thanks again!

19 Games

Halfway through the season seems a good time to compare this season & the teams competing within it to others.  Maliciously, the Premier League has already played the 20th round of fixtures, and played it so quickly that i'm behind, but still, it's worth a look at some historical trends & markers.  I've got the last 6 first half seasons I can compare & rank & this article is designed to look at some of the characteristics 2014-15 has & compare with the 5 seasons that preceded it. Data for previous years is under-available!  This gives us a sample of 120 & all rankings will be 'nth in a sample of 120'.

Chelsea v Man City

For the first time since 2011-12 we look to have a potentially enthralling 1v1 dual for the title.  Last season had Arsenal top at this point & Livepool's charge was late & long whereas 2012-13 was Man Utd's stroll.  2011-12 found Man Utd & Man City locked together at the top after 19 games with identical records, a scenario that would repeat right down to the last minute of stoppage time in the very last game & Aguero's late title winner.  The two sides ended up 19 points clear that year (both on 89 v 70 next best) & this year is shaping up similarly but with Chelsea replacing Utd in the mix.  Indeed, Chelsea's 46 point total after 19 games is only matched by Ferguson's legendary swansong & City's 43 points is only superceded by the aforementioned & the 2011-12 pair.   These are clearly two elite level teams & are superior to the rest of the league by a clear margin.  What fascinates me is how closely they resemble each other in the numbers & despite the media & casual observers happily coronating Chelsea since roughly late August, it leads me to believe that they are likely to push each other throughout.

*Of course since I wrote this, Chelsea & Man City have managed to accrue identical records, which more than reasserts my point!

Shots For
There are no historically strong pure shots teams in the league this year, the best teams rank as follows: 

1. Arsenal: 23rd/120
2. Man City: 24th
3. Chelsea: 26th

We do have the two worst shots for teams in the sample though:

1. Aston Villa: 120th/120
2. Hull: 119th
3. Palace: 111th

Swansea, Leicester, Sunderland & Burnley have all posted historically sub-par shots totals too.
In fact, there's has been a trend towards less shots over time with quite a big drop off this year.  There's a possibility methods of collecting could have changed but without knowing that we have a clear trend:

Shots Against

For there to be balance in the universe we need an equal opposite & conveniently we find similar but opposite trends in shots against.  There are no historically terrible shots against teams:

1. Burnley: 93rd/120
2. Leicester: 85th
3. QPR: 84th

We do have the best shots against team in the sample though & two more scoring very well:

1. Southampton: 1st/120 
2. Arsenal: 4th
3. Chelsea: 5th

Here we see the trend again:

Quite naturally, these figures map themselves onto shots on target:

Shots on Target For
Best:

1. Chelsea: 15th/120
2. Arsenal: 21st
3. Man City: 24th

Worst:

1. Hull: 117th/120
2. Aston Villa: 116th
3. Burnley: 115th

Shots on Target Against
Best:

1. Chelsea: 1st/120 (immediately ruined by the Tottenham game!)
2. Southampton: 3rd
3. Man City: 5th

Worst:

1. QPR: 106th/120
2. Burnley: 92nd
3. Sunderland 81st

No surprise that Chelsea and Man City show up very well in these categories & the 'bad' totals are posted by a wide mix of relegation possibles.  Again we see the natural trend that less shots-->less shots on target-->less saves.  Interestingly the goals totals have moved by a smaller degree than other components which hints at a possible increase in shooting efficiency over time:

Shot Ratios
(TSR & SoTR)

At the extremes, only Chelsea's shot on target ratio stands out as significantly high.  Arsenal, Man City and Southampton round out the best 4 clubs here & each has decent if not outstanding figures.  Similarly, the batch of worst teams are much of a muchness here, without being historically awful.

Save%

Everton's save percentage is the worst on record.  Roberto Martinez is also responsible for 4th, 7th, 18th & 30th positions whilst at Wigan.  Under par & worrying for Everton's current predicament.  Intriguingly, given the 'Pardew situation' Newcastle & Crystal Palace round out this season's top 3, in 6th & 9th overall.  Bad figures that may well improve but partially underline the problems Pardew both faces & has created himself.  In 2005-6 he guided West Ham for half a season to terrible totals then took over at Charlton & couldn't keep them up...

Man Utd, Aston Villa, Swansea & West Ham are running the highest save percentages, none of which is historically high but it will have helped some of their current success.  It's perfectly possible that these percentage could remain high throughout the season, but the list of teams that have recorded very high save percentages is littered with teams that generated a good year off the back of this & failed to follow it up once a degree of readjustment hit the following season.

One such example is... er.. Everton 2013-14 (75%).

Conversion % For

Aston Villa & Burnley are running at about 6% conversion at the half way point (quickly redeemed by Burnley in week 20!) and rank 119th/120 and 116th/120 respectively.  This is very bad.  Even worse when factored against the relegation rate for seasonal 6% shooters: 3/3.  Limping to 7% or better would be a big help.

A clutch of teams are all running decent percentages:

League average is 10%.  Some of these teams are the true elite, some of them are experiencing good seasons driven to a degree by fortune & the other team is Everton.

Conversion dominance

There are 7 teams in that chart above & 6 of them are backing up their excellent but possibly short lived high conversion rates with a similarly excellent low conversion % against ranging from 7-9%.  Some of these are the true elite, some of them are teams experiencing good seasons driven to a degree by fortune & the seventh team is Everton.

Everton are the only one of these 7 to not have a conversion dominance & are conceding at a league high rate of 13%.  Put simply, at various times, the goals have flown in at both ends in Everton games.

There are no historical outliers on either the good or bad sides here but WBA, QPR & Burnley are all running high deficits here & Newcastle & Liverpool aren't too far behind them.  The story of conversion is a powerful one when understanding the relative successes of teams during a season.  It can vary wildly & quickly but mid-term trends can be extremely informative when stood against a wider context.

Other bits

• WINS: 11 wins all but guarantees top 4, only Chelsea & Man City qualify
• GOALS FOR:  40+ goals? ^ditto
• GOAL DIFFERENCE:  +14 has been enough for top 4 since 2009, Southampton AND Man Utd join City & Chelsea in passing this test.
• POINTS: Everton 2013-14 are the only team to have more points than Man. Utd (37 to 36) & not qualify for the top 4.

Week 20, quick thoughts

As an indicator of how vulnerable some statistics can be to one game, week 20 had a few notable entries, none more influential that the Tottenham v Chelsea game which hacked a good few chunks from Chelsea's excellent defensive numbers, in particular (average shots on target rose from 2.5 to 2.8) whilst giving a much needed boost to Tottenham's generally average figures.

Elsewhere, Villa's 0-0 has seen their conversion rate drop back down to c.5%.  With a pitiful 11 goals somehow powering a half decent points total, they face an arduous season.  In contrast, by scoring 3 at Newcastle, Burnley broached the magical 7% mark for the first time since the first game.  If they can stay above it, they've got a chance.  Meanwhile, Palace look like they need a Pulis but are gonna get a Pardew & WBA have hired the right guy; never pretty but highly effective, his teams have always managed to build from a defensive base & outperformed woeful attacking figures.  West Brom's opponents are unlikely to be scoring at 12% for long.  Palace's conversion went from 6%F/11%A to 8%F/9%A under him last year & his Stoke teams never once conceded at above league average rates or ran a conversion deficit of any significance.

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Thanks for reading!

FA Cup this week & the normal blog will reappear as per usual after the next round of league matches.
Thanks for reading & if you liked it feel free to share!

Meanwhile: if you missed them:

'Unlucky Neil Warnock'

'Yuletide Round Up'

& the article that killed of Pardew (maybe)