Robin van Persie Really Isn't Afraid to Miss.

A year ago I wrote a couple of posts about the shooting characteristics of Robin van Persie under the general heading of "strikers shouldn't be afraid to miss". The data was from 2010/11, so the Dutchman was still an Arsenal legend, rather than a dangerous opponent from a championship seeking rival who makes a once a season visit to the Emirates stadium.

To summarize the post, when comparing the chances of a van Persie goal effort resulting in a score against location corrected efforts for the other main Arsenal shooters, the Dutchman was clearly superior. However, in terms of accuracy, it was his group of colleagues that were more likely to hit the spot and no matter where the shot originated from, van Persie was slightly more likely to miss the target completely.

I speculated that the rest of Arsenal's strikeforce was taking the mantra of "make the goalie work" to rigidly, taking less risks and more guaranteed applause by failing to shoot towards the less accessible areas of the goal for fear of missing. In short, van Persie's shot placement was more adventurous, more prone to missing the target completely, but ultimately more rewarding in terms of goals scored as a result of this efforts struck towards the periphery of the goal, generally being more difficult to save.

I intended to compare van Persie's shot placement to see if he was indeed working with finer margins, but instead the post became a general look at shot placement as well as shot power on the regularly seen location based shooting models. That post turned up last month as Power and Placement , so now is a good time to revisit the original van Persie venture.

Placement is an obvious factor in determining the outcome of a shot, although the effect of shot power is likely to have a much greater influence on the final result. From data used in the previous link, shots hit from identical pitch positions, but aimed closer to the frame of the goal, increase the likelihood of scoring. But when going from a weak to a more normally paced shot from the same spot, the improvement in expectation is generally many times greater. Shot pace is likely to be a major factor in calculating goal expectancy, but it just isn't generally available, so we will have to include placement alone, largely ignorant of the potential effect of shot power.

Although both keepers and strikers have a "natural" side, it's unlikely, given the numerous body shapes a player has to adapt to get a shot away that one top corner is very much different from the other. Therefore, to see how van Persie's shot placement may have enhanced his performance compared to a shot location based model alone I summed his total top corner, bottom corner and central attempts and saw how they compared in terms of frequency to those of similar contemporaries, namely the top scorers from all the other Premiership sides from 2008 onwards and his fellow Arsenal strikers over the same time scale. This approach also boosts sample size.

Percentage of Shots Hitting Particular Areas of the Goal, 2008/13.

Player/Team.	Top Corners.	Lower Corners.	Top Central.	Lower Central.
R. van Persie.	15%	54%	8%	23%
Arsenal exc. RvP.	12%	50%	7%	31%
League Ave. Top Scorers	13%	50%	8%	29%

The impressions from the original post appear to be confirmed by more granular data. Robin van Persie does appear to find the top and bottom corners proportionally more often than his now former goalscoring teammates, as well as beating the pooled average of the top scorer from each permanent member of the Premiership club since 2008. Only Villa's cumulative pool of leading scorers has bested van Persie's ability to hit the corners over the last five completed seasons. For those fond of anecdotal evidence, the Dutch striker has also hit the woodwork 17 times in the last two seasons, perhaps indicating that he is likely to be shooting with an extremely narrow margin between probable glory and individual shooting failure.

By daring to miss, the premise of the original post appears sound, RvP seems to be boosting his scoring rate at the expense of his accuracy.

van Persie outperforms a simply model based around just shot location. If we then incorporate shot placement into an updated version and van Persie (or any other player) consistently outperforms that version, we need to entertain the idea of including other variables, such as shot power. And then onto defensive pressure or player movement and quality of assist. Models always fail to include every possible factor, but as long as we know what is included, they remain valuable. What's absent is the likely cause of discrepancies and this can lead to fruitful, further investigation.

Perfecting shooting models is an onion that's going to take some peeling.

Strikers Shouldn't Be Afraid To Miss.An Appreciation of Robin van Persie.

As the seasons draw to a close across Europe the process begins of evaluating players for end of year awards or as potential transfer targets during the next transfer window.Inevitably the main spotlight falls on attacking players and goalscorers and the way in which these type of positions are judged is gradually changing as a result of the availability of more extensive data.Where there was once simply goals scored and games played anyone can now access more informative granular data such as shots,shots on target and shots to goals ratios.

Excellence in any form rarely requires numerical verification,so it seems sensible to start with the acknowledged best and review their statistics in an attempt to spot any indicators of potential greatness.Each of the top clubs possess fine strikers,but as this year has demonstrated,few are better than Arsenal's Robin van Persie and he was equally impressive last season when he scored 18 times at a rate of almost a goal per starting appearance.I'm going to use van Persie's scoring statistics from 2010/11 when he contributed 18 Premiership goals to Arsenal's seasonal total of 72 using data kindly provided by OptaPro.

Van Persie made 25 appearances in the Premiership for Arsenal in 2010/11,including six from the bench.His 18 goals came from 85 attempts on goal,neglecting 12 blocked efforts,so his strike rate was an impressive 21%.Of his 85 attempts,43 either ended up in the back of the net or required the keeper to make a save,so his accuracy of 50.5% was equally noteworthy.

If we compare van Persie's shooting a scoring prowess to his fellow Arsenal strikers and midfielders,including the likes of Fabregas,Arshavin,Nasri and Walcott we find that he leads his teammates in both categories.The rest of the team minus the defenders hit the target with just 49% of their combined attempts and scored only 13.3% of the time.

Van Persie's Shooting and Scoring Efficiency Compared to that of his Fellow Midfielders and Strikers.

2010/11 Season.	% of Shots on Target.	% of Shots that Resulted in Goals.
Robin van Persie.	50.6	21.2
Arsenal's Other Midfielders & Strikers.	49.1	13.3

We shouldn't really be surprised at these figures,Robin van Persie is primarily a goalscorer and a big part of that talent is an ability to convert chances.Combined with his superior accuracy,he appears to possess the classic requirements to be a top striker,namely an ability to hit the target and lethal finishing.However,these raw numbers may be deceiving and with further investigation another less obvious and potentially important facet of van Persie's talent and personality may become apparent.

Nearly a quarter of van Persie's goal attempts were made from a distance of ten yards or less compared to just 16% of those attempted by the other Arsenal players and it seems reasonable to assume that hitting the target in a fluid sport such as football becomes more difficult the further away you are from goal.Using OptaPro's 2010/11 seasonal shooting data for van Persie and his colleagues I've used regression analysis to project how likely it is that each group firstly scores and secondly hits the target from varying distances.

How Likely Arsenal Were to Score from Varying Distances Based on 2010//11 OptaPro Data.

The data is quite naturally sparse as we move further from the goal and the line of best fit is only a approximation,but van Persie's preeminence amongst his team as a prolific converter of chances is confirmed.His projected conversion rate is superior for the entire range of distances from the penalty area and beyond.If goalscoring is a talent,this graphic demonstrates that van Persie certainly possess it and given the choice of a chance falling to either him or a another random Arsenal player,van Persie should be the choice.

Again this merely confirms RvP is an excellent striker and we already knew that,but the second graphic may go someway to shedding new light on how he is so successful.A large proportion of van Persie's goal attempts are made close to the goal,25% are within ten yards and the closer you are to a target the easier it is to hit it.If we run another regression on how likely it is a shot will hit the target with varying distance,we see that van Persie is actually less accurate than his teammates at most shot distances.His overall superior accuracy of 50.6% compared 49.1% that we saw in the first table results from his shots on average originating from closer to the goal than those attempts from other Arsenal players.

How Likely Arsenal Were to Hit the Target from Varying Distances Based on 2010//11 OptaPro Data.

So now as an Arsenal fan if you want to see the opposing keeper have to attempt a save you are slightly better off if the chance falls to a random Arsenal attacker or midfielder rather than the team's consistent leading scorer.

These results are from one season and just one team,so they may not be repeated over other seasons or in larger sample sizes,but potentially we have a tremendously talented striker who is better than his teammates at converting chances regardless of shot distance.However,he is also more likely to miss the target completely than are a group of comparable colleagues at all distances until the rates converge around 30 yards from goal.

One of the qualities that former England coach Sven Goran Eriksson looked for in his players was an absence of fear of failure and perhaps the numbers we are seeing here shows that van Persie has this trait.His "poorer" accuracy at all distances compared to his colleagues may be because he is prepared to shoot early or aim for the areas of the goal where the margins for error are small.His more conservative teammates may be inclined to play safer and be content to initially force the goalie to make a save.Van Persie's longterm payoff from being free of any anxiety caused by an increased "failure" rate for accuracy may be an increased successful goal conversion rate because his on target shots are more difficult to anticipate or save.

We are conditioned to look at performance indicators and assume that increases in efficiency is always the way to go,but perhaps in the case of goalscoring an inferior rate of shooting accuracy is actually the driving force behind an increase in the ultimate aim of increased goal conversion rate.Is the coach's maxim of "Don't be afraid to miss" being embraced by the very best?