The influence randomness and luck can have on a soccer team’s performance is common knowledge. This influence is usually accentuated in individual games but it is still present across an entire campaign. How lucky have Burnley FC been in the Premier League this season? Read on to find out.
The Premier League surprise package of 2017/18
The 2017/18 Premier League season is shaping up to be a resounding success for Burnley. When the season started back in August the Clarets were one of the favourites for relegation (priced at 2.25) and now, as the season draws to a close, they are still in contention to finish sixth and qualify for the Europa League.
Last season was the first season the club reached 40 Premier League points - an even greater achievement when you consider this came after immediate relegations in their two previous efforts in 2009/10 and 2014/15. So what has caused Burnley’s dramatic improvement; is it a tactical master class? An increased physical effort across the board? Or is it just luck?
In Nick Pope Burnley have the league’s best homebred goalkeeping performer and have also been represented at international level by defender James Tarkowski.
Sean Dyche’s side has also confounded many advanced metrics that predicted a season of struggle as his defensive orientated approach continues to out-perform most expected goals models.
Often when a side’s actual record is at odds with their underlying performance metrics, one of two extremes is used as the explanation. It is either assumed that randomness is the overwhelming cause or a tactical quirk, such as Dyche’s packed defensive set up is given priority.
However, single causes in such a complex team sport as soccer rarely wholly accounts for deviations from a prescribed norm and it is much more likely that multiple factors, some transient, some that will inevitably become less effective over time, are at the root of Burnley’s recent success.
Randomness is gradually becoming recognised as a constant influence on single match results and even entire seasons, while squad churn, through natural ageing, injury and replacement eventually impacts on a side’s ability to implement a gameplan, particularly as it becomes more widely appreciated by their opponents.
Therefore, even with the increased level of granular data that is now available, it would be unwise to overfit the events of the immediate past to our projections for the upcoming future.
How should we view Burnley’s 2017/18 Premier League season?
It’s undeniable that Burnley have been lucky in the conventional sense of the word regarding red cards. Up until December 2017, Burnley’s opponents had received five red cards to Burnley’s none and in three of those games the final result was more favourable to Sean Dyche’s team than had been the case prior to the sending off.
Burnley will have had little control over their ability to open the scoring in the first half of 2017/18 over and above the simulated average and future games will see a less extreme distribution.
Unusually, three of those dismissals came prior to halftime, when the average time of a red card is around the hour mark - giving Burnley ample time to make their numerical advantage count. This statistic becomes particularly advantageous when you consider a red card is considered to be worth about +1.4 goals over an entire 90 minutes.
Such advantages are almost certainly unique to Burnley’s first half of the 2017/18 campaign and while cards will be shown in subsequent seasons there is absolutely no guarantee that the split favouring them will be as extreme and regular in the future.
Randomness is unfortunately synonymous with luck and that also implies a side has gained something that is undeserving.
How to measure how lucky Burnley have been
In taking a probabilistic view of events created within a sporting context, we are merely exploring the wide spectrum of outcomes that may have occurred, along with their likelihood from the best, but far from perfect models we have constructed.
We can use such models to simulate the likelihood of events occurring in a game, such as which team was more likely to open the scoring.
A side that relies heavily on a defensive approach, as Burnley do, will benefit enormously by being able to score first. They are then free to give full rein to their defensive set up while becoming increasingly threatening on the break.
Prior to the New Year, Burnley opened the scoring in eleven of the 21 Premier League matches that were played during that timeframe. They also took 34 of their current 52 points during this period, almost three-quarters of their total points tally.
So in the first half of the season, when they were at their most prolific, they not only enjoyed over 200 combined minutes playing against a numerically depleted opposition, they also scored the opening goal more frequently than not.
If we look at the 17 teams whose improvement stretched to seven or more places (more in line with what we have witnessed with Burnley), the fall was an average of five places in the following campaign.
We can perhaps only assume that red cards will be less favourable in the future, but we can make a fair estimate of whether 11 opening goals in 21 matches is a sustainable return for a side of Burnley’s underlying attacking statistics.
The most likely number of times Burnley might have opened the scoring, based on the simulations of expected goals for every chance created and faced by Burnley in the first half of the season, is six times.
Burnley’s actual total of 11 or more only occurs in around 2% of simulations.
There are twenty sides competing in every Premier League season, therefore, this seemingly rare first goal event for Burnley will occur for some team, simply through random variation on a fairly regular basis.
But it’s likely that Burnley will have had little control over their ability to open the scoring in the first half of 2017/18 over and above the simulated average and future games will see a less extreme distribution.
We have identified two possible causes for Burnley perhaps overperforming their core abilities, neither of which seem likely to remain at the levels enjoyed in 2017/18.
In addition, novel tactics rarely persist without evolution. For instance, Stoke’s long throw gave diminishing returns as opponents became more familiar with the strategy.
How will Burnley perform next season?
Other teams may have profited from such a happy alignment of factors in the past as Burnley have this season and we can see how a side subsequently performed following a season of apparent great strides, as Sean Dyche’s men showed from 2016/17 to 2017/18.
If Burnley maintain their current position, they will have risen nine places compared to the 16th they managed in 2016/17. Since the inception of the 20-team Premier League, 34 teams have improved their position by five or more places from one season to the next.
Of those 34 sides, 11 improved again in the next season, but on average the sides fell by three places. If we look at the 17 teams whose improvement stretched to seven or more places (more in line with what we have witnessed with Burnley), the fall was an average of five places in the following campaign.
Many of these sides who saw such a major improvement were probably lauded as having made a significant step forward. They include Newcastle’s 2011/12 team, who jumped from 12th to 5th, only to fall back to 16th in 2012/13 and West Ham, whose jump from 15th to 7th was merely a prelude to relegation in 2002/03.
Despite the case being vigorously made for Sean Dyche as a defensive mastermind, he has been partly dependent upon an outstanding shot stopper (and De Gea aside, goalkeeper’s performances tend to fluctuate from season to season), the red mist of opponents and outstanding post shot placement from his strikers - again, a transient skill.
The historical odds firmly suggest a decline in 2018/19.