Last weekend, after Arsenal lost against QPR, many Gooners might have shared a wistful moment reminiscing the chance Robin van Persie missed. Those who don the blue of Chelsea probably look back at this Torres miss early in the season and wonder if everything would have been different had that gone in and led to a comeback against United. The Kop faithful will undoubtedly feel their side can win any argument regarding missed opportunities. Indeed, almost every single football fan, irrespective of the club they support and their position in the League, must have had a Redknappesque “my old woman could have scored that” moment at least once during this season.

There are few moments in a game more frustrating than a player missing a gilt-edged opportunity. Unfortunately, we don’t have enough fact-based analysis of such incidents and usually just have to go with clichéd opinions from commentators like, “You’d have put your money on him scoring that”, or “That’s a rare miss from [player name]”, and so on. It’s probably one of the reasons why many fans find football punditry hard to digest.

To an extent we can’t blame anyone because there just aren’t enough facts available as far as clear-cut chances are concerned. There are so many variables involved that it would be hard to find a concise and practical definition that pleases everyone.

One would have to look at so many factors when analysing a clear-cut chance (CCC):

the distance from goal

the technique of the player to whom the chance falls

whether it’s on his stronger or weaker foot; or his head

attacker’s body shape and orientation

height of the ball

condition of the pitch

positioning and quality of the defenders and the goalkeeper

pressure applied by the defender(s)

the weight on the pass

And so on. This article on StatDNA and this one on Arsenal Column provide very interesting discussions on the topic while highlighting the complexities involved.

Opta do provide numbers for clear-cut chances created and converted. In their own words this is one of the “subjective stats” that they offer. Since the definition is not, er, clear-cut, we probably cannot form any definitive opinions but assuming consistency on the part of those recording the stats, maybe one can attempt to create an engrossing discussion on the subject.

Please note that the stats used in this article were compiled prior to the weekend’s fixtures and only include numbers from the first 30 matches.

Let’s start with total clear-cut chances created and converted by each team and their relationship with total goals scored. In the figure below, the blue line represents total gilt-edged chances created by each team while the red one charts the number of these chances that were converted. Total goals scored by a team is in green.

With a single glance it is apparent that these curves are very similar. Most of us, even without any statistical background, can guess there must be strong correlation between the numbers.

The peaks represent sides that are creating and scoring the most. Few will be surprised that the current top four are, in the same order, creating and converting the most clear-cut chances. United, City, Arsenal, and Spurs also form the top four in total goals scored.

At the other end of the table it’s not so simple. For instance, if you look at the last team on the right, Wolves show a steep bump in the red curve indicating a high conversion rate, but not so much in the other two meaning they aren’t creating as many chances or scoring many goals in general.

The other stand-out observations from the graph are,

Liverpool have created a lot of high quality chances – fifth highest in fact – but are converting very few

Bolton have not been able to create easy opportunities for their attackers. They’re rock bottom with 26 chances created or less than one per game

Sunderland have created a lot more chances than Bolton but have converted only 11, joint second-lowest with Bolton

Wigan are the side that has scored the least number of goals, 10, from so-called sitters

The average number of clear-cut chances created by the sides is around 53 or 1.77 per game

United lead the way with 89 and City are close behind with 88 at roughly 3 clear-cut chances per game

The median for goals scored from such chances falls around 20. Again Man United lead with 40 conversions while Man City have 38.

Next Page: Comparison of clear-cut chance conversion and regular chance conversion….

CCC conversion Vs overall chance conversion

Keen observers must have already noticed large variations between the conversion rates. The blue line in the following graph charts those numbers.

The red line shows the corresponding conversion rates for all goals scored from total shots on and off target.

One can immediately conclude teams score a lot more frequently from clear-cut chances than they do from other opportunities but you probably didn’t need a graph to tell you that. However, since the blue line is so high up, it does make one wonder how low the chance conversion rates from other opportunities would be for the red line to be in the middle.

Think of it this way, the average CCC conversion figure is around 38 percent while the corresponding number for total chances is around 13 percent. That means the conversion rates for other opportunities must be lower than 13 percent. Indeed, when I looked at long range shots earlier, Man City had the best success rate that was just under 8 percent and the average was around 3.4 percent. Of course, that analysis was done in February and the sample size of games does not match, but the numbers do provide a reasonable indication of the vast difference in the probability of success with different types of chances.

That’s not to say teams should only look to create easy chances. As we can see Wolves, surprisingly, have the best conversion rate for sitters. But their overall conversion rate is low and this correlates well with the fact that they had zero goals from outside the box when the earlier analysis on long-range shots was undertaken. In fact, City and United had the highest conversion rates for shots from distance showing the importance of having multiple scoring options. But I digress, let’s keep the focus of this article on high quality chances.

While the average CCC conversion rate is around 38 percent, only 6 teams have converted a lower fraction of their chances. Wigan (23.26), Sunderland (26.19), and Liverpool (28.99) are the worst offenders. In contrast, Wolves top the charts (45.24) with Man United (44.94), Newcastle (43.9), QPR (43.59), and City (43.18) in close proximity. 9 teams convert between 38 and 43 percent of their easy chances. Stoke, Everton, and Spurs score from approximately one in three gilt-edged opportunities.

Wigan and Liverpool are the only teams below the 10 percent mark in total chance conversion rates. Their inability to convert clear-cut chances has obviously had a big impact on their respective seasons. In contrast Sunderland have a healthy 14.4 percent overall rate, which is higher than average, despite their second-lowest CCC conversion success. Again a higher number of goals from outside the box – they were third highest by early Feb – would have helped their cause.

Another very interesting observation is that the top teams, with all their big stars, are not head and shoulders above the rest when it comes to clear-cut chance conversion. For instance, Man United have an overall conversion rate of over 20 percent which is approximately 50 percent above the average that’s around 13. But their success from easy opportunities, while close to the top, is only around 18 percent above average.

It indicates that the difference in the skill level of players is not so big as to have a significant impact on their ability to convert high quality chances. Could it be that the real differentiator here is the amount of such opportunities created and not the conversion?

Liverpool fans will obviously disagree as they fret over their side’s inability to finish. Supporters of Bolton, on the other hand, will point to their above average conversion rates and lament their inability to create more. Perhaps the key variables are different for each team and might even vary with each season based on personnel, tactics, and form.

Finally, I want to take a look at the ratio of goals scored from high quality chances to total goals scored.

This graph is really very different from all the others. Essentially, it depicts the gap between the red and green lines in the first figure above. The closer the two lines are, the higher proportion of a team’s goals are coming from clear-cut chances.

So Aston Villa clock over 70 percent with 22 of their 31 goals coming from gilt-edged chances. While high, this number is not very healthy as it suggests they have fewer other avenues of scoring. Swansea and Wolves are the only other teams for whom such goals account for over 60 percent of the total goals scored.

At the other end, Sunderland score less than 29 percent of their goals from easy chances. This would have been a phenomenal stat if their total goals scored figure had been very high. But at the moment, it’s as much a reflection of their inability to convert simple chances as of the diverse ways they can score goals.

The average is around 48.76 percent with the top three achieving between 52 and 56 percent.

Conclusions

This data is inherently very subjective and hardly conclusive.

One could say the top teams are creating a lot of high quality chances and converting a fair proportion of those. They also achieve a healthy balance by scoring goals from other types of chances thereby increasing their total goals count.

Beyond that it’s hard to generalize over such a broad spectrum. Each team probably has its own set of strengths and weaknesses.

Some of the numbers, especially the CCC conversion rates, are very close together and a couple of games could change the shape of the curve. However, one would not expect a team to fall from 40-45 percent to the 25-30 percent range. At that broad level we can see indications of struggle or strong points for most of the sides.

With that I’ll leave you to form your own conclusions. Remember these stats are available to subscribers on a seasonal and match-by-match basis. To look at other details for your team or to make your own comparisons pick the package that suits you best.