Monk Loses the Winning Habit.

At the end of August 2014, two sides, Swansea and Chelsea were vying for the lead in the Premier League table with a 100% record from three matches. Aston Villa were third.

So it represented business as usual for Mourinho and a validation of the soon to be written raft of complementary articles about the bright new manager in charge at Swansea, Garry Monk.

As of yesterday two of those three teams have seen managerial change and Mourinho's tenure hangs by a Champions League thread.

Monk's hot start to the season was prolonged enough to earn him a place on the Daily Telegraph's shortlist of six for manager of the season, along with the beleaguered Mourinho and the subsequently dispensed with Sam Alladyce.

A near 50% attrition rate in the blink of an eye.

It is becoming commonplace to increasingly acknowledge the role that luck plays in shaping a relatively short, skill based competition, such as a Premier League season.

More data hungry models in late 2014 were already suggesting that Swansea had been relatively shot shy and fortunate even as they remained buoyant, only slightly removed from their August heights,

An abundance of 1-0 wins, seven in total by May, further hinted at a solid mid table side inflated upwards by random, most likely non repeatable events.

Premier League managers, always looking over their shoulders.

Outsiders are never privy to the inner workings of the professional relationships with a football club that may drive change, but it was particularly unfortunate for Monk that an immediate see-sawing of narrowly contested 1-0 games fell so badly for him in 2015/16.

Five such league defeats and a cup exit since August 2015.

Extremes, such as Monk may have benefited from in 2014/15, tend to be less extreme in the future, but fueled by euphoria and congratulatory broadsheets, they tend to become the normal expectation from both the fan base and employer.

Swansea's 14 actual points through 15 games are around a win shy of their most likely total based on shot model simulations and they have created enough to have had a 1 in four chance of bettering the 20 or more points that would have invited a more prosperous New Year.

The reality is probably that, in part at least, a straight comparison has been made between the 0.9 points per game this term and the near 1.5 points per match in 2014/15 and knees have been jerked.

Random variation gives and it sometimes cruelly takes away.

Rebranding Stoke.

The view that you're as good or bad as your last performance usually flourishes in the online club fora and the soundbite world of football punditry.

So it was hardly surprising that Stoke briefly rose to the dizzy heights of everyone's favourite second team following their comprehensive and visually pleasing defeat of second placed Manchester City on Saturday lunchtime.

Stokealona or my own favourite, Inter City, briefly trended.

The tendency to stereotype teams and players based often on stale evidence from seasons long gone, is a trait that continues to surprise.

On Saturday the realisation gradually dawned on the BT commentary team that even players who remained from the rump of Tony Pulis' ingeniously devised, but widely despised system, could actually participate in a passing based evolution.

Quotes from opposing managers who should really have known better suggesting "We know what to expect from Stoke", while packing the team bus with six foot plus defenders, was amusingly familiar even while the Hughes revolution stumbled uncertainly from possession poor to possession normal.

Pass completion rates for the likes of Cameron, Whelan and Shawcross were poor under Pulis not because those players couldn't pass the ball, but because they were required to implement an approach that at its most extreme coveted distance over retention.

Following the fairly amicable parting of the ways, Pulis' brand of survival at all costs football swept through the lower reaches of the Premier League, first at Palace, later in a delicious irony at WBA, sending the passing stats of competent players plummeting in the process.

Raw shooting differentials failed to spot the trade off between shot quantity and shot location, as Stoke under Pulis invited the opposition to shoot frequently from distance, while they bundled in sufficient goals at the other end from just inside the six yard box.

Shaqiri, along with Afellay, Arnautovic, Bojan, Joselu and Muniesa, "He plays for City!".

Hughes' Stoke has partly borrowed from the Pulis blueprint, recruiting flawed jewels from a wider market. Careers marked by injury, under achievement or a temperament that prefers to invite a post game red card, rather than celebrate a brace of match winning goals, has allowed the assembly of unprecedented talent in the Potteries.

But while plaudits are a welcome change, Stoke's longterm prospects should perhaps be viewed in the context of their accumulated stats. Just as Pulis' Stoke were legitimately better than a swift glance at their shot differentials implied, Hughes' infinitely more entertaining version may be better judged on their statistical achievements this term.

Individual match performance will invariably fluctuate. One or two perceived improved results do not make a trend and Stoke are more usually to be found in the lower half of current league simulations, a handful of expected points below their actual current total of 22.

The Hughes revolution hasn't taken Stoke, puns apart, into the higher echelons of European football. they've merely entered the Premier League mid table tactical mainstream.

Diego Costa, Head & Shoulders Above the Rest?

There have been some great stats on potential finishing ability posted here on Dan Kennett's twitter feed. Naturally the focus was on Liverpool players, particularly Daniel Sturridge and the post proved timely following Wednesday night's 6-1 away victory at Southampton.

Identifying different levels of finishing ability is always going to be challenging in a sport where scoring opportunities are relatively rare.

Squad rotation, substitution and injuries often deprives strikers of playing time and few manage more than five attempts per 90 minutes.

Even in Dan's comprehensive list of the highest achievers, only a handful of players have exceeded 10,000 minutes since 2011, the time it allegedly takes to master a skill.

Topping the list of currently active Premier League strikers is the recently rested Diego Costa. A 23% conversion rate has been achieved in less than 100 attempts, a small sample size compared to the remaining players in Dan's list, who average nearly 300 attempts each.

Therefore, although Costa's conversion rate is well in excess of Aguero and Sturridge, his nearest EPL challengers, there must be a suspicion that his 23% rate is unsustainable, long term compared just under 15% for the other two.

Who Needs a Fit 16% Striker Every Week!

There are a variety of approaches that are currently available try to identify finishing skill.

Expected goal models add an extra level of insight. But they are data hungry and potentially susceptible to rare events, such as deflected shots. Ultimately they only measure a player's deviation from the norm expected by that particular shot based model, which itself is almost certainly incomplete.

It is also rare to see such model based analysis address the likelihood that any over or under performance occurred merely by chance.

If instead we assume the chances presented to these out and out strikers are broadly similar, we can see if the spread of conversion rates is wide enough to imply differing levels of finishing skill within the chosen group.

This approach focuses more on the role of random chance and incorporates sample size, while assuming chance quality is similar for each player.

In short, it is a flawed, polar opposite approach to that of an equally flawed shot based model.

Regressed Conversion Rate for EPL Strikers 20011/12-2015/16.

Data Credit - Dan Kennett.

Player	Regressed Conversion Rate.
Costa	0.149
Hernandez	0.148
van Persie	0.147
Aguero	0.147
Sturridge	0.147
..............................	..........................
Defoe	0.142
Lukaku	0.141
Suarez	0.141
Ba	0.139
Bony	0.139

The spread seen in Dan's numbers are just extreme enough to conclude that there is some evidence that finishing skill may exist. 

Costa remains the highest rated finisher, but his numbers are regressed by over 90% towards the group average because of his relatively low number of attempts. We have to go to the third decimal place to elevate him above the next four highest players, including Sturridge.

Similarly, the gap between the most and least efficient finisher is now just 1%, rather than the 12% seen in the raw data.

It would be unusual to see a wide range of true finishing abilities at the elite level of a professional sport. 

There may be tentative evidence to suggest that a narrow gap does exist (perhaps traditional scouting could contribute the eye test) and Daniel Sturridge is towards the top of such a pecking order...but can he do it on a bitterly cold night in a minor cup competition in January at the Britannia Stadium!