AFCON 2015: Congratulations (again) to Ivory Coast

#prci: Tour du Stade FHB du Président Alassane Ouattara et les joueurs pic.twitter.com/ySGsiYHkuI
— Presidenceci (@Presidenceci) February 9, 2015

Look closely into the picture in the retweet above, which I have posted from the official Twitter account of the Presidency of the Côte d'Ivoire. You will see Yaya Touré holding the coveted AFCON trophy and sitting beside the Ivorian President atop the front-car in the cavalcade doing the victory lap in front of the home-crowd. 

The Ivory Coast's victory over Ghana in the AFCON 2015 final on penalties has ended a 23-year wait for the trophy. And, well done to them. Bien joué. Spare a moment, though, for Ghana. They have been trying unsuccessfully since their 1982 AFCON crown to add a fifth AFCON trophy to their national cabinet. The wait goes on.

I have written about my main observations at Football Every Day and at KettleMag so I won't take up any time here rehashing those pieces. 

Naturally too, the end of the AFCON 2015 tournament has left me bereft of a dynamic subject matter to write about such as the one only AFCON tournaments can really provide. 

However, the passing of time has made me think about what I can write about next and I have decided to focus on football-topics much closer to home - namely, Belgium. So, over the next weeks (I hope longer, but we will see where it goes) the central theme to my writing is going to be on the football of Belgium and the Netherlands. 

As, Belgium and the Netherlands have been otherwise referred to as the Low Countries and my surname so happens to be Low, I thought this a good opportunity for a bit of wordplay...

So, as a working title for the next few posts, I am going with:

Lowzer's Low Country Lowdown 

What I aim to do is put on the lenses of a pseudo football analyst to try and dissect what happened and why in the worlds of Belgian and Dutch top-flight football.

So, look out for the posts. I do hope you enjoy them.

AFCON 2015: Deserving Finalists, Skill Overcame Luck, and Luck Ran Out

Cast your mind back to one of my earlier posts on the 2015 Africa Cup of Nations where I used statistics to look at the skill and luck teams had in the group games. According to these stats, 6 of the Quarter-Finalists had benefitted from a lot of luck in the group stages. This came from my PDO vs SoTR chart: 6 of the Quarter-Finalists had PDO values of over 1000. 

Now, if you recall PDO is a measure of luck - the higher the number the more the luck the team has had. You arrive at a team's PDO figure by adding the percentage of goals scored from shots on target, to the percentage of goals conceded from shots on target against them. More broadly, the score percentage and the save percentage. The SoTR - Shots on Target Ratio - is the proportion of shots on target a team has of the total number of shots on target by the two teams. The higher this number is, the more skill a team has as it indicates they dominate the number of shots on target.

For reference, I bring back the PDO vs. SoTR chart from the group stages below. The chart clearly shows that Ghana and the Ivory Coast exhibited the highest skill - as indicated by SoTR - in the group stages of all the Quarter-Finalists (those teams with a Gold or Silver icon beside their three-letter country code).

This chart got a bit of love on Twitter in the past couple of days as it shows that despite a limited sample size (16 teams competing over the course of 24 matches) the SoTR (Skill) PDO (Luck) comparison yields some intuitive insights as to why teams succeed and/or fail. Additionally, the simple fact that there are no "lucky" teams - as shown by PDO, anyway - in the final shows that using this chart has some power in explaining things in this particular tournament.

Again, this is a small sample of data, and it must be stressed that Ghana faced, in Guinea and Equatorial Guinea, two massively inferior opponents in the knockout stages. The Ivory Coast have overcome bigger challenges to get to the final, so it will be an interesting one to watch. If, the skill levels (SoTR) continue to hold some predictive power - if I could call it that? - Ghana looks like the winner.

I've said it before. I'll say it again: I can't bloody wait for this final!

AFCON 2015: Congratulations to Ghana

Ghana booked their place in the 2015 final of the Africa Cup of Nations by beating the hosts, Equatorial Guinea, 3 - 0 in a game that was marred by unfortunate crowd troubles, which caused a 30-minute stoppage in play.

The Black Stars showed composure, patience and quality throughout the game highlighting the gulf in quality between themselves and the hosts. Equatorial Guinea looked off the pace and lacking in the cultured footballing knowledge their Ghanaian opponents carried throughout the contest. Equatorial Guinea were in fact unable to muster a shot on target on Ghana's goal. Ghana outshot the hosts 15 - 4.

Ghana have now not allowed one shot on target against them in their two knockout stage games. Guinea in the Q-F were the other opponent that failed to register a shot on target against Ghana.

Going into the second Semi-Final of the tournament, there was a lingering question as to whether or not Equatorial Guinea could continue their fantastic Cinderella-story into the final in front of the adoring home crowd. However, Ghana quickly frustrated Equatorial Guinea and therefore the home crowd throughout the first-half. Some of the Equatorial Guinea players' reactions to refereeing decisions visibly vented the collective frustration felt by the home fans. In truth, much of the frustration owed its origins to the gulf in class between the two sides.

While it took Ghana over 40 minutes to break the deadlock, they effectively killed the game as a contest when they did so (CAN Orange video). In the 40th minute, Christian Atsu threaded a through-ball through to Kwesi Appiah who was clumsily brought down by the ill-timed (and ill-judged) charge by the Equatoguinean goalkeeper. Jordan Ayew dispatched the spot-kick with aplomb. Mubarak Wakaso added Ghana's second in first-half stoppage-time as Ghana hit Equatorial Guinea on the counter-attack from a corner-kick the hosts wasted. To repeat a complaint my dad always has of corner-kicks: "you've got to get it past the first defender". Equatorial did not, and they paid the penalty.

André Ayew had a chance on 54 minutes to put Ghana 3 - 0 up but did not get enough contact with his header, Kwesi Appiah also had a chance to make it 3 - 0 when he was put through 1-on-1 minutes later but could not finish either. Then - alas,-  in the 75th minute Kwesi Appiah was again put 1-on-1 with the Equatoguinean goalkeeper - who again foolishly charged out from his line - and Appiah showed all the calmness needed to pass square to André Ayew who showed his composure by finishing at the far-post from just outside the six-yard box.

Trouble later ensued with the crowd but in truth Ghana were never really in any trouble or doubt. I am bloody looking forward to the final.

AFCON 2015: Congratulations to the Ivory Coast

Wilfried Bony again proved crucial to the Ivory Coast in their 3-1 Semi-Final victory over the Democratic Republic of Congo (DRC). He provided the assist for Yaya Touré's screamer, which opened the scoring in the game, and for Gervinho's second goal of the tournament, which put Ivory Coast 2-1 up and effectively ended the contest.

Bony also drew 4 fouls on him, joint-highest on the field with Serey Die, the Ivory Coast's defensive midfielder. This shows how much of an inconvenience Bony made himself to the DRC defence throughout the match.

The shooting statistics I covered in my last post actually do a pretty good job of explaining what happened in last night's Semi-Final. Although the DRC outshot the Ivory Coast 19 - 14, both teams fired 7 shots on target. Shooting on target implies an element of skill: accuracy. When this skill is converted into goals that is an even more desirable attacking skill. 

As my last post demonstrated, throughout this year's Africa Cup of Nations the Ivory Coast has been more skilful in front of goal with a goal-per shot on target ratio of 0.43 (meaning roughly every 2.5 shots on target they shoot, one goal will come from it) to the DRC's 0.29 (meaning they take, on average, slightly more than 3 shots on target to score 1 goal). 

Furthermore, the shot differential statistics - shots taken minus shots conceded - over the course of the tournament showed the DRC generally take more shots than their opponents do. Defensively, the teams had fairly similar records in terms of the goals conceded per shot on target conceded statistic. They both hovered slightly over 0.2 implying their opponents averaged taking five shots on target before scoring a goal.

On the night, it took a brilliant effort from Yaya Touré to break the deadlock. The DRC's equaliser came from a penalty, and they looked good again in the game, only to concede a goal on a turnover of possession due to a hospital pass from Yannick Bolasie being taken over by the Ivory Coast and Bony and Gervinho did the rest. 

As Jonathan Wilson has written in the Guardian, and as I wrote here, it seems like this Ivory Coast side is content to play on the counter-attack. It seems to be paying dividends... 

AFCON 2015: More on the Semi-Finals & Predictions

Here is another look at the teams in the Semi-Finals:

Team	Shot Differential pg	Shot OT Differential pg	Goals conceded pg	Goals scored pg	Goals per Shot OT	Goals Conceded per Shot OT
DRC	2.5	0.75	1	1.5	0.2857	0.22222
CIV	-0.75	0	0.75	1.5	0.4286	0.21429
GHA	-1.5	1.25	0.75	1.5	0.5455	0.50000
EQG	-3.75	-1	0.5	1.25	0.3333	0.10526

From left-to-right:

• Shot Differential per game (pg): this statistic is the number of shots a team takes minus the number of shots their opposition takes, per game. The Democratic Republic of Congo (DRC) tend to take 2.5 shots per game more than their opponent whereas Equatorial Guinea take 3.75 fewer shots per game than their opponent.
• Shots on target (OT) per game: this statistic is the number of shots on target a team takes minus the number of shots on target their opposition takes, per game. Ghana takes 1.25 shots on target more than their opponent, per game, on average, whereas Equatorial Guinea takes 1 fewer shot on target than their opponent per game.
• Goals conceded per game: self-explanatory really, it ranges from the DRC's concession of one goal per game to Equatorial Guinea's much better 0.5 goals conceded per game. Of course, this is a bit of a misnomer, it is much more like they concede a goal every other game.
• Goals scored per game: again, self-explanatory. The DRC, Ivory Coast and Ghana all score around 1.5 goals per game, on average. Equatorial Guinea scores at a slightly slower rate than the other teams.
• Goals per shot on target: this statistic is the number of goals the team has scored in the tournament divided by the number of shots on target they have taken. Ghana has the highest rate at 0.54 which translates as scoring a goal for every 2 shots they hit on target. Ghana has hit only 11 shots on target in this tournament - the lowest out of the Semi-Finalists - but has a better conversion rate than the other teams. The Ivory Coast are not far behind them and the lowest again is Equatorial Guinea.
• Goals conceded per shot on target: this statistic is the number of goals a team has conceded divided by the number of shots on target they have defended against in the tournament. Ghana is again the leader in this statistic with a rate of 0.5, which translates as for every two shots its opponents have fired on target on their goal, one is a goal. The best rate belongs to Equatorial Guinea at 0.1, so teams have taken around 10 shots before they scored against Equatorial Guinea.

What can we take from these numbers? ** past performance is not a guide to the future, or is it?

DRC vs. Ivory Coast (Wednesday)

If form is any guide the DRC will outshoot the Ivory Coast in total shots. As for shooting on target, the DRC will marginally outshoot the Ivory Coast again. It is likely both teams will score, especially as the DRC averages conceding a goal per game. If the Ivory Coast can outshoot the DRC, limit their shooting and maintain their 0.43 goals-per-shot rate, it will be the Ivory Coast's game. 

Predicted Winner: Ivory Coast

Equatorial Guinea vs. Ghana (Thursday)

If FIFA rankings are any guide, this should be easy for Ghana. There are 81 places between the two team's rankings. However, Equatorial Guinea take some momentum into this game. They also don't concede many goals per shot on target against them. On average, the Equatorial Guinea sees 4.75 shots on target against them per game, but concedes at a rate of 0.10. However, Ghana don't take much encouragement to score. And, judging by the excellence of Atsu, the Ayews and Appiah, let alone whether Gyan is fit for the game, Equatorial Guinea will have their work cut-out.

Predicted Winner: Ghana

AFCON 2015: Semi-Finals and the insight from a few statistics

I last left you, dear reader, talking about the role of luck in the quarter-finals. This post aims to look ahead at the Semi-Finals and consider what we may expect from the teams involved in terms of tactics.

We Can Expect Attacking Football

The good news for the neutral is that goals per game have been increasing slowly but steadily as the tournament has progressed. The chart below demonstrates this with goals per game (total goals scored per round of matches/matches played) shown by the upwards sloping green line. The increased number of goals per game is welcome news, as too is the increased number of shots per game (and also the shots on target).

The Semi-Finalists have become more accurate and more effective in front of goal

The next chart I have made plots the shots taken per shot on-target on the x-axis against the shots taken per goal scored on the y-axis. Shots taken per shot-on target is a figure representing, on average, how many shots the team needs before it shoots one on target. The shots taken per goal scored figure is, plainly, how many shots it takes, on average, for the team to score a goal. I have labelled the data points with the three-letter country code and the game-round. So, DRC 1 means Democratic Republic of Congo's 1st Group game. CIV QF means Ivory Coast's Quarter-Final. What's important to note from the chart below is the generally downwards trend towards the bottom-left corner of the chart. If you look specifically at Ghana it is almost a linear relationship downwards. 

In short, teams are getting more shots on target and needing fewer shots to score.

Another way of looking at this improving efficiency and potency of the attackers on display in the Semi-Finals is by returning to the 'Attacking Effectiveness' graph I have used in the past based on concepts from Ben Mayhew of experimental361.com. The higher the amount of shots taken and the lower the number of shots to score a goal is the key bit of information needed in this chart. The DRC are way out in terms of shots taken but their Quarter-Final was a bit of an exception to the other three and so seem an outlier. The other three teams, Equatorial Guinea, Ghana and the Ivory Coast are all pretty well clustered together and there is not much between them in terms of attacking effectiveness...

Defensive Weaknesses or no?

Turning our focus onto defence our next charts focus on defensive games. The chart below focuses on the shots faced per game against the shots taken. The important pieces of data to look out for are how the data move from game 1 to the quarter-finals. By that, it appears Equatorial Guinea and the Ivory Coast have the most consistent styles of play in that they both generally take below average (indicated by dotted blue line) number of shots, and cluster around the average number of shots defended (faced). This means they have reasonably busy defence and attack in their games. Ghana and the DRC are both harder to pin-down as a style as their data points variate over the chart. 

Ghana's data point 'GHA 1' in the chart above is from their game against Senegal - their only defeat so far. What this goes some way in telling is that if teams apply enough pressure on Ghana's defence it will eventually leak. However, if you look at Equatorial Guinea's data for shots taken they rarely take over 10 shots per game. As I have mentioned in my posts on the role of luck, Equatorial Guinea have plenty of it on their side, particularly in front of the home crowd. I just feel Ghana have too much strength in their attack for a defence like Equatorial Guinea's to withstand.

In the other contest, the Ivory Coast's defence has yet to stand up to an attack which shoots as many times in a game as that of the DRC's. The Ivory Coast did well to withstand Algeria but their back line looked shaky at times. Similarly, the DRC were made to look silly twice against Congo, and barely crawled out of the group stages. In the last meeting between the two nations the DRC won 4-3 so again I am expecting a lot of goals.

I am expecting a lot of goals actually, because:

These defences struggle to prevent chances being made inside their own penalty area...

What I have done with the chart below is illustrate the proportion of the total shots the Semi-Finalists have faced against their opposition in their four previous games in this tournament, that have been within their own penalty area (data from the fantastic whoscored.com and idea vaguely based on work by Seth Dobson).

In short, I expect goals. 

Further Analysis of the AFCON 2015 Quarter Finals: Luck must run out, or does it?

In my last post I talked about how skill and/or luck helped the quarter-final victors take their spoils.

In this post I am looking at another chart to explore the topic from another angle.

The chart I have made looks at PDO (Luck) of the teams playing in the quarter-finals of the tournament. It compares their group-stage PDO to their PDO statistic from the quarter-finals. Of course, this is imperfect as a comparison because the group stage PDO is over 3 games whereas the quarter-final PDO is from just one. However, the comparison is insightful as it shows that of the 6 teams with PDOs of over 1000 in the group stages, 4 were eliminated in the quarter-finals: Algeria, Congo, Guinea & Tunisia.

PDO indicates luck. Luck is subject to the laws of gravity. In short, it is possible that those four teams' luck ran out in the quarter-finals. Spare a moment to sympathise with Tunisia all the same.

Interesting to also note how 'lucky' the Ivory Coast and Equatorial Guinea were in the quarter-finals when thinking about what may happen in the semi-finals... As I said before, I think the counter-attacking performance of the Ivory Coast was excellent and, overall, deserving of victory. Furthermore, the Cinderella-story of Equatorial Guinea in front of their home crowd is a force to be reckoned with.

AFCON 2015 Quarter-finals: Deserving Winners or Unlucky Losers?

This weekend was a mammoth weekend of football which obviously means mountains of potential writing material. However, since my recent focus has been on the Africa Cup of Nations tournament, it seems only fair (and logical) to continue in that vein. (And, the less said about Saturday's new-firm semi-final at Hampden the better...)

In my last post I discussed my observation a seemingly large number of goals have been scored in the last 30 minutes of these games. It makes sense, of course, as a knock-out cup tournament like the Africa Cup of Nations is all about the elimination of teams until a winner is crowned. Naturally, teams will push more in the dying minutes as their survival in the competition depends on it.

Luck or Skill?

Another theme of this tournament I have tried to explore is what role luck plays compared to skill. Work done by the excellent James Grayson using English Premiership team-level data has shown that even in leagues, and over time, metrics such as percentage of shots on target or percentage of shots saved boil down to luck much more than skill.

Using data from the bbc football match summaries, I graphed team skill and luck from the quarter-finals. I calculated a team's Shots on Target Ratio as a measure of skill and PDO as a measure of luck. The chart** is below:

Reminder: PDO (Luck) centres on 1000 and is mean-reverting. What this means for the purposes of this explanation is that teams at the higher-end of PDO have had more luck on their side than the teams on the lower-end of PDO. Additionally, we would expect PDO to converge on 1000 over time.

According to the PDO figures in the chart above, the Ivory Coast and Equatorial Guinea were luckier than Ghana and the Democratic Republic of Congo (DRC) were to be victorious in their respective quarter-finals. Ghana, for example, did not allow Guinea a single shot on target in their game and made it look easy. The DRC made a truly inspired comeback against Congo scoring four goals in slightly over 25-minutes. But they also shot nearly double as much as Congo did (21 to Congo's 12).

Hard luck or good tactics? Or, something else?

So, I sat there thinking about luck and skill...

After watching the Ivory Coast manage to beat Algeria 3-1, I thought it would be incredibly difficult to use any figures (apart from goals scored, obviously) to prove that Ivory Coast were deserved winners. Algeria seemed to dominate the pace of play, and seemed to be a much stronger team. Additionally, Ivory Coast looked very shaky in defense.

However, Herve Renard - the Ivory Coast boss - made an insightful comment about how he arranged his players tactically to overcome the individual strengths of Algeria, a team he considered the 'best in the tournament'. He told the BBC:

"We needed to be very well-organised and try to counter a team who are very strong individually." (emphasis my own)

In the same interview, Renard explained he thought Algeria were much better on the ball and going forward, but he set his team up specifically to make the most of the pace of the likes of Gervinho and Max Gradel to supply Wilfried Bony on counter-attacks. And, it worked.

Algeria themselves played a different kind of game to how they played in the group stages: they had more possession and shot more. In the group stages they averaged under 50% of the possession in games. In this quarter-final they had 60% of the possession. In the group stages they took around 7 shots per game (on avg.). In this game, they took double that, 14 shots. But Ivory Coast had all the right answers to Algeria's change of style. And, Ivory Coast had Wilfried Bony to thank who scored twice and drew Algerian defenders to foul him four times. Algeria could have done with a presence like his in their attack...

In the Tunisia-Equatorial Guinea match, however, I think poor refereeing luck played a huge role in assisting the hosts progress to the Semi-final. An extremely soft penalty awarded to Equatorial Guinea in second-half stoppage time seemed to be so unfair on Tunisia. I think the image below says much more than my words can...

I think this @AP image pretty much sums up the Tunisian mood right now... #AFCON2015 pic.twitter.com/urAwWRxF7k
— Joe Crann (@YesWeCrann) January 31, 2015

Dominance in the Quarter-Finals? Or, was it really luck?

I also wanted to look at the games in another way so I looked at the shot-dominance in the quarter-finals. Recall from my earlier post when I dived into a preliminary statistical sweep of the group games that the sweet-spot of the graph below is the bottom-right corner. This is where teams take many shots and limit the number of shots taken against them. In this corner is Algeria and the DRC. Now, from the PDO vs. SoTR chart above we already established the DRC ran out deserved winners. And, from what Renard said about his tactics against Algeria we see that the counter-attacking style of play is not well accounted for in these charts. 

chart concept from Ben Mayhew of experimental361.com

An interesting part in the chart below is how closely matched Equatorial Guinea and Tunisia were over the course of 120 minutes - at least in terms of shots. Again, it is hard for these charts to take refereeing decisions into account...

** Updated on 2/2/15 at 16:30 to include revised PDO chart

Football: it is a game of two-halves

I'll discuss why teams reached the quarter-finals in a later post as I need some time to collect my thoughts. Until that time congratulations to Ghana, Ivory Coast, Democratic Republic of Congo and Equatorial Guinea. Commiserations to Algeria, Tunisia, Guinea and Congo.

The game of two-halves (and extra-time, when needed...)

I've been sitting here thinking about whether there is something near a 'normal distribution' of the times at which goals are scored in football tournaments. For example, it makes sense if a high number of goals are scored in the last ten minutes as teams pile on the pressure with their last-ditch efforts because the team's survival in the tournament is at stake.

I plan to dig into this topic a little bit more tomorrow but I'll give the overview right now.

The first of these two charts shows the timings of goals scored grouped by 15-minute segments and extra-time. The first-half goals are in blue, the second-half goals are in purple. Extra-time goals are in red. The second-chart explores these as percentages.

The charts show pretty plainly that in the Africa Cup of Nations - so far - teams are leaving it pretty late to change the outcome of the game. 34 of the 61 (or 56%) goals scored so far have come after and/or on the 61st minute of games. 

What's more, 44 of the 61 goals (or, 72%) scored so far have come in the second-half. That seems like a big skew to me.

I have put this post here as a bookmark (if you will allow me) to explore further. It'd be interesting to know if this timing-of-goals pattern is mirrored in other international tournaments (such as the Asian Cup, for example).

Luck or Skill: updated chart

With big thanks to Ben Mayhew of the excellent experimental361.com for alerting me to the errors in the skill vs luck chart in my last post.

I re-ran the numbers and got a much more normal looking chart, which I have put below. 

As PDO is mean-reverting you would expect Ghana and Ivory Coast to become luckier and the teams with PDO above 1000 to become unluckier as the tournament progresses.

However, the big caveat as Ben Mayhew pointed out to me, is that these figures (PDO & SOTR) are usually traced over the course of a league season and not in a cup-tournament. Cup tournaments generally ride much more on luck due to their duration than leagues. 

So, take these figures with a pinch of salt...

Footnote 1: If you recall, PDO is a measure of a team's luck. The higher the figure, the higher the luck - the logic goes. A team's PDO consists of its Shot percentage + its Save percentage. There are excellent summaries on PDO on James Grayson's blog (here) specifically about football and a comprehensive explanation of the measurement's origins in Ice Hockey here.

Footnote 2: The whoscored.com do not perfectly add up: shots on-target for add up to 177, whereas the shots on-target against add up to 173. No biggie, but it means no team sits on the 1000 line for PDO, as it is supposed to.

Africa Cup of Nations 2015: A dive into the statistics of the group stages...

*** updated 31/01/2015 to include updated PDO vs. SoTR chart

In my last post I ran through some fairly general impressions of the 2015 Africa Cup of Nations so far. Among other topics, I bemoaned the lack of goals and the high number of draws. In this post I develop some analysis of the Africa Cup of Nations by relying heavily on … wait for it … statistics.

By using data provided by whoscored.com I set out to try and understand what aspects of a team’s game have helped them progress to the quarter-finals. In short, I wanted to understand if it is more down to skill or luck.

I also wanted to see if there is any way of guessing how the quarter-finals will go based on trends or patterns in the data.

What I have found out is:

1. It is a combination of skill and luck;
2. 4 of the 8 quarter-finalists (50%) enjoyed over 50% of the possession in their group matches --> dominating possession is just as successful as...er, not dominating the possession. It would appear...;
3. Only 3 of the 8 quarter-finalists (38%) took above the average number of shots per game --> shooting more than your opponent is not always a guarantee for success;
4. Having a busy attack and quiet defence is no guarantee for progressing to the quarter-finals in this year's tournament; and,
5. It is definitely NOT good defending keeping the number of goals down in this years tournament.

All of this begins with…

Dominance

One of the first topics I wanted to explore was the concept of dominance. My reasoning is the most dominant team should surely win the game, right?

In the first chart of many below, I compare the shots per game a team takes and the shots per game it defends against. The x-axis (horizontal) shows the number of shots the teams take per game. The y-axis (vertical) plots the shots per game teams defend against. Broadly speaking my logic went like this: “if you take more shots than your opponent, you dominate the game”. In terms of statistics, comparing shots taken to shots defended, we have a simple (but crude) measure of ‘game dominance’.

The dotted blue lines plot the ‘average’  (the same goes for all charts used) which is roughly 11 shots for and 11 shots against per game. Using the example of Senegal, they shoot above average against their opponents and they tend to face fewer than average shots on their goal.

If you think about the chart as four quadrants, the ‘most dominant’ quadrant is that one on the bottom-right. It is the area where teams shoot the most and manage to stifle shots coming against them: in other words, they are strong in attack and have a relatively quiet time defensively. The top-right quadrant is the busiest quadrant. It is where teams have taken many shots but also faced many shots. You get the picture.

Data sourced from whoscored.com and graph idea from Ben Mayhew experimental361.com

So, in looking at this chart, we see that Senegal, Zambia and Burkina Faso all belong to the bottom-right quadrant, but none of these teams progressed to the quarter-finals.

This chart only shows whether the team has attacked its opponents more or has been more on the back foot. It says little about the effectiveness of the attack…

But you have got to score to win

True. The Democratic Republic of Congo are the only team in the quarter-finals to have scored fewer than 3 goals so far. Algeria have scored the most of any team at the tournament so far. They also take the fewest number of shots to score a goal:

Team	Goals Scored	Shots Taken	Shots per goal
ALG	5	22	4.4
TUN	4	35	8.8
CON	4	33	8.3
GHA	4	38	9.5
EQG	3	27	9.0
MAL	3	28	9.3
CIV	3	30	10.0
GUI	3	22	7.3
RSA	3	33	11.0
SEN	3	44	14.7
DRC	2	37	18.5
ZAM	2	38	19.0
GAB	2	34	17.0
CAM	2	30	15.0
CPV	1	32	32.0
BFA	1	47	47.0

But it is not always so simple...

How many shots must a player take, before he scores himself a goal?

The answer is not blowing in the wind, certainly not in Equatorial Guinea. The chart below compares the shots a team takes to the number of shots it takes the team to score. This is a crude measurement of shooting skill, or the potency of the team’s attack. If a team takes more shots to score a goal, generally speaking, they have less skill than a team that takes fewer shots to score a goal.

Data sourced from whoscored.com and graph idea from Ben Mayhew experimental361.com

The measurement in this graph is of ‘attacking effectiveness’, i.e. how effective the attack of one team against the other. Generally speaking, the teams in the bottom right of this chart are in the sweet-spot. They take a lot of shots, so they play with a high intensity AND they don’t take many shots to score a goal. It seems fairly reasonable then that Ghana and Tunisia – two of the stronger teams in this tournament – are in the sweet-spot. But, what about the other two favourites: Algeria and Ivory Coast? Well, both Ivory Coast and Algeria don’t take as many shots as Tunisia and Ghana but the four teams are similar in the aspect of not needing to take many shots to score a goal. Interestingly, seven of the eight quarter-finalists take below average number of shots to score a goal. In other words, generally speaking the teams with highest attacking skill have progressed. The Democratic Republic of Congo is the exception: it has progressed to the quarter-finals taking an above average number of shots to score a goal.

What is a good chance?

Alright, so shooting accuracy is one thing, but it is also important for attackers to be supplied with plenty of chances by their teammates. So, I was sitting there thinking (wahey): "how could I come up with a stat simple enough to understand that shows a ‘good chance’ objectively?"

Most of us would agree that if a team advances play to a position where they can shoot from inside the opponent’s box, they have created a good chance to score. So, I developed a measure of what a good chance might be: 

I have taken the number of shots a team makes inside the box as a proportion of the total shots they take (per game). So, if a team takes 8 shots inside the box per game and takes 10 shots per game, its “good chance” proportion is 80%. Make sense?

In the chart below, the ‘sweet-spot’ is in the top right-hand corner. Here, teams have a lot of possession and more than half of their shots are inside the opponent’s box. 

Senegal, Burkina Faso and Gabon all populate this quadrant, however, none progressed to the quarter-finals. If we look to the bottom-right quadrant, we see three quarter-finalists - Equatorial Guinea, Ghana and Congo - populating the area. These teams create good chances (>50% of the shots they take are inside of the opponent's box) but have less than 50% of the possession.

Data sourced from whoscored.com graph idea my Charles Low (my own)

So, then, it is not all about creating "good" chances...

The Importance of Possession

My belief that possession is key to winning games (as well as scoring, obviously!) probably reveals my bias approaching the data, so I should make it clear. My belief is based on seeing the way the tiki-taka style popularised by Barcelona, (i.e. possession is king) has come to dominate the game in recent years. When I think of “teams of my generation” very few could compare to Barcelona under Pep Guardiola or the Spanish World Cup winners of 2010.

I wanted to dwell on this thought for a little longer. Think about it like this – how does a team convert its possession? Does it create a high number of chances but has a weakness of conceding a lot of chances on the counter-attack? Think Arsenal…

So, to try and translate this into figures I developed a "shot dominance ratio". I called it this way as I constructed a ratio of shots taken by a team to the total number of shots in a game. So: 

shot dominance = shots for per game / (shots for per game + shots against per game). 

If shot dominance > 0.5 the team has taken more shots than its opponent.

Possession is the average possession figures over three games. Again if possession is greater than 50% the team had more possession than their opposition. So, the teams in the top-right of the chart (i.e. with over 50% possession and 50% shot dominance) dominated the game in terms of possession and shooting – broadly a measure for chances to score. Only five teams – Democratic Republic of Congo, Cameroon, Ivory Coast, Burkina Faso and Senegal – had more possession and shot more than their opponents. Three of those teams are going home.

Data sourced from whoscored.com and graph idea Charles Low (my own)

What about the defence?

Less is made of the defence, but it is interesting to look at nonetheless. What this chart below reveals is really interesting. Remember from my last post I said there have been a pretty low number of goals in these games? Well, that is NOT explained by good defending. So, the explanation is either excellent goal-keeping, or poor skill in front of goal – because it is certainly not due to lack of chances being created.

Again, if we think about the chart as four quadrants, the top-left quadrant is where good defensive teams are situated. It is the quadrant where teams don’t allow many shots to be taken on their goal and it is also where many shots must be taken before a goal is scored against them. If we consider Equatorial Guinea way up there in the right-hand quadrant we could view it that their defence has done well – it takes their opponents many shots to score a goal. However, their defence (and goalkeeper) are probably well over-worked as the team faces a lot of shots, on average, in games.

Data sourced from whoscored.com and graph idea from Ben Mayhew experimental361.com

Something Else?

So, I sat there thinking (wahey): “how can it be that the dominance of possession and shots cannot explain the team’s performances?” How is it that teams who have more of the ball and shoot more than their opponents do not qualify for the quarter-finals? It could be down to luck. But, it could also be down to skill.

In football analytics there is a way of providing a rule-of-thumb to quantifying skill and luck. Skill is described as the Shots On Target Ratio (SOTR) [shots on target for/total shots on target]. Luck is described as shooting % + saving %. It is taken as a given that it requires great skill to shoot a high percentage on target. In the luck category, it is considered a great fortune to save a high percentage of shots against you. [NB: it makes sense right – you ever been watching a game and you thank god the opposition striker couldn’t hit a barn door?!] I owe a great deal of praise to Seth Dobson’s fantastic blog 2-2-6 for explaining these concepts.

Basically, the higher the PDO, the greater the fortune a team has. And, as luck is subject to laws of gravity this spells bad news for teams with PDO of above 1000. In the graph the teams are grouped by colour according to where they finished in the groups. The quarter-finalists are the gold and silver marks. What we can see broadly is that 6 of the quarter-finalists have benefitted from luck - as PDO would have it - so far. How long will it last?

Conclusions

So, what have I learned? I have learned that making charts is a great way to waste time and provides some insight into the beautiful game. However, I still have a gut feeling Ghana are going to win this thing…