Examining the factors behind corner betting
By Mark Taylor Jun 13, 2014
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Read this World Cup corners betting article, which examines what drives the propensity of corners during a game and how to calculate total or individual corner counts for a soccer match. If you want to be successful, understanding the factors behind corner betting is vital.
Are corners valuable?
Despite his love affair with the English game, Jose Mourhino has struggled with the fans obsession with corner kicks. The award of a corner is met with unique enthusiasm by English fans, and Mourhino’s remark was the precursor to an ongoing debate within the burgeoning soccer analytics community regarding the real value of corner kicks.
Argument against the importance of corners, hinge on their low goal conversion rate, coupled with a largely anecdotal threat of being caught by a rapid counter attack from the defending team.
Supporters of the corner kick counter with a favourable comparison between a corner kick and the comparable alternative, a final third pass. Also, even an unsuccessful corner can still result in the attacking side retaining possession of the ball.
Typically goals from corners account for just over 10% of the total goals scored in the EPL, with their importance varying across different teams. Sides such as Stoke can be grateful that their prowess from corner kicks has helped them establish themselves in the top flight and both Manchester teams have maximised their return from the humble corner.
Meanwhile, major domestic and European finals continue to feature game deciding goals from corner kicks, though may contribute to a gut based assessment of their value that stats simply don’t support.
The recent FA Cup final witnessed two goals from corners, following on from the only goal in Wigan’s victory over Manchester City in 2013. And Europe’s most prestigious match has featured game changing scores from corners by eventual Champions League winners, Chelsea and Real Madrid in two of the last three finals.
So despite Mourhino’s reservations, corners, at the very least provide a significant goal scoring subset to enhance open play goal totals and fans will continue to celebrate their award in a sport where scoring is both difficult and relatively uncommon.
Is team ability a factor?
Along with many secondary markets, such as bookings, the number of corners a side is awarded tends to go hand-in-hand with more fundamental indicators of relative team ability. Bookings accumulate more rapidly for a team that is forced to defend and by a similar logic, a side that is involved in the majority of the attacking intent during a match will also be more likely to accumulate more of the game’s share of corner kicks.
Soccer’s singular approach to scoring is responsible for many of the statistical trends that are observed within matches. For example, an NFL team can turn territorial advantage readily into points on the scoreboard by field goals.
In soccer, there is no secondary prize on the scoreboard for gaining territory. All a soccer team gains from being higher up the pitch is the right to try and create a goal scoring opportunity, and until a goal is scored both teams are still equal, regardless of territory or possession.
What a soccer team does tend to accumulate, through attacking intent, are the products of attacking their opponent’s goal, most notably, shots, but also corners. Corners are successfully defended goal attempts or threatening situations that have been temporarily neutralised and just as penetrating, but ultimately thwarted offense in the NFL yields field goals, soccer’s constant attacking tends to yield corners.
Using the EPL as an example
If we average the number of corners won by EPL teams with multiple seasons since 2006 we find that corners do correlate reasonably well to attacking prowess. The better sides, which we would expect to do more overall attacking, such as Manchester United, Chelsea, Liverpool and Arsenal each appear at the top of the table, while relegated, weaker or recently promoted sides dominate the foot of the table. Overtly attacking wing play may be able to tweak a side’s corner count upwards, but general weight of attacks appears to be the dominant factor.
“Better teams win more corners” is a pleasingly simple and intuitive conclusion, but as with many apparently obvious statements in soccer this one has issues of causation and context. The pregame talent gap between teams gives an indication of how a match is likely to finish, but because of the low scoring nature of soccer, underdogs sometimes win outright or hold a superior side to a draw, while the actual match outcome appears to be a partial driver of corner counts.
As we’ve seen better sides as a group, denoted by a higher pregame win probability accumulate more corners. But the conclusion has to be qualified because almost universally, teams win even more corners in similar matchups when they go onto lose the match compared to when they win it and the disparity is greatest when the gulf in class is at its highest. Massive pregame favourites win an average of six corners when they win, but nearly eight and a half when they lose.
When they trail, the best also have the ability to press their opponent’s goal even more and if they spend a large part of the game attacking, but not scoring, they gain even larger numbers of corners. It is also common to see a corner successfully defended by the concession of a further corner.
So corner counts come about through a mixture of pre-defined talent and in game effects – and we can only be reasonably well informed about the former. Using the matches played in the EPL from 2002 to 2012 as a proxy for the less common and relatively data poor international competitions, the proportion of corners won in a neutral venue game by a side that could be expected to score (P) proportion of the total goals is given by:
Proportion of Corners=0.1818+(0.6365*P)
So if a tournament game was expected to have an average of 2.6 goals and team A was expected to score 2 or proportionally 0.77 of those goals, they would expect to win 67% of the corners awarded.
In the graph below, we’ve plotted the distribution of individual corner supremacies from the perspective of the pre-game favourite. On average, that’s a side with just over a 50% chance of winning the match.
The favoured side in this sample wins just under two more corners than their weaker opponents, but the range of possible outcomes is large, with a significant minor chance that the inferior side may win more corners. Bettors may gain an edge in Corner markets but understanding how factors like last minute formation, line-up or tactic changes might influence such variance.
The plot also illustrates how the chances of increasingly larger corner handicaps being covered falls away for the average Premiership favourite.
Total match corners in the EPL over the same period averaged around 11 and the distribution of possible outcomes is also shown below. Typical with all of the major leagues there is a very slight skewing of the distribution caused by a lower limit of zero, but the possibility for totals to occasionally reach well into the twenties.
These corner characteristics, while not drawn from international competition are likely to exhibit the broad characteristics of international tournament soccer. Of the various international websites, UEFA, alone provides even the slightest of corner statistics for individual sides and only partly for individual matches.
We can begin to bring together all these strands to create general pointers when estimating corner predictions.
Predicting corner count at the World Cup
Some teams may exhibit the apparent ability to either win more than the expected proportion of corners or participate consistently in matches with many or few corners than normal. This may be a real effect of tactics or squad make up. However, unless it is backed up by copious amounts of data, it is also likely to be an artefact of reduced sample size at international level.
If you feel that the effect is real, be prepared to temper that conviction by combining these estimates with the expected averages for the tournament. For example, at Brazil 2014 the present consensus is that games will average 10 total corners per 90 minutes. This is exactly where it landed for the opening game (Brazil did however gain four more than Croatia).
Accept that international data is sparse and therefore may be prone to outliers skewing the figures. Spain will not play the likes of Georgia at the finals of a major tournament, but they may do in qualifying. That Spain can accumulate more corners than their opponents might not be a surprise, but their 83% share in qualification owes a lot to the 16 corners with just a single reply against Georgia.
Similarly, Argentina’s qualifying record appears to indicate that they gain fewer corners on average than their opponents, despite being second favourites to lift the World Cup. But once again a deeper look at the statistics shows a 20-2 corner defeat in Ecuador.
A single outlier can quickly produce misleading averages in limited samples.
England vs. Italy
Italy will begin their World Cup against England in Manaus on the 14th of June. Italy will be slightly shorter than England to win the match therefore the strong trend for favoured sides to gain most corners will favour the Azzurri.
Qualifying results offer England some comfort. Both Italy and England participated in games that, on average produced above average total corners, but England gained around 70% of the available corners, whilst Italy’s share was split virtually 50/50.
England’s lion’s share may have resulted from a tactical approach, possibly based around pressuring the second ball in the box. But a more visible cause are two matches against San Marino and one against Poland, where the corner contest was won by a combined 47-5, boosting both totals and supremacy in the type of matchups that won’t be available at the World Cup. Italy gained similarly, but to a lesser extent, most notably against Malta.
So we have a strong general trend, slightly favouring Italy and observations based on a limited amount of games, which may contain a proportion of atypical contests that suggest England have recently done well in gaining and avoiding the concession of corner kicks, while Italy may struggle to dominate in terms of corners.
Available quotes suggest that Italy will be narrowly favoured to take more corners than England, indicating that the bookmakers are siding with the more general trend. This result would repeat the outcome at Euro 2012, when Italy “won” the corner count 7-3. Although by delving into reports, it is likely that at least one of Italy’s seven corners came in extra time, reinforcing the need to verify data sources wherever possible.
Click here to see latest World Cup corner data odds
*Odds subject to change
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