Thursday, 16 August 2012

The Case For Crosses.

The recently departed Euro Finals provided a paradox for advocates of different styles of play. Spain largely did away with the conventional centre forward, choosing instead to play intricate, short passes in the final third while patiently waiting for an opening to appear. Meanwhile many of the remaining teams, England among them threw crosses into the box and reaped a fairly substantial reward. The Barcelona/ Spain approach is certainly widely admired and Andy Carroll's towering header against Sweden, rather than being seen as a magnificent feat of precision crossing by Gerrard and athletic finishing by the forward, was regarded as the act of a team playing in a tactical backwater.

Crossing it has been suggested is not only outdated, it is also a waste of precious possession, an inefficient mode of scoring and a hostage to luck rather than skill. Teams throw the ball in to the mix and hope for the best.

Fortunately, data now exists that can help to help quantify and compare each approach. I therefore collected data for every cross attempted during the 2011/12 EPL season and recorded the frequency of which the ball reached it's intended target and the number of times the cross resulted in an immediate goal.

The first charge often leveled at crosses is that they require large amounts of luck to result in a goal. If luck was the over riding factor in scoring from crosses, we would still see a variation in conversion rates between teams. Toss a coin 800 times (the average number of crosses attempted by a team in a season)  in 20 batches and some coins would appear to be more adept at scoring heads than would others simply as a result of natural, random variation. So just because Chelsea require less crosses to score one goal than do Wolves, we cannot automatically assume that Chelsea are more skilled at crosses. Instead we need to see if the conversion rates from crosses varies between teams in such an extreme way that we can conclude that the spread is due not only to natural expected variation, but also player input that we may attribute to differing levels of skill. This may be the crossers ability to more accurately deliver the ball or the strikers ability to lose his marker and direct the ball goalwards.

One down...72 To Go!
In the table below I've listed the average number of crosses each EPL side would require to register a goal by the first player to receive the cross based on analysis of each side's crossing conversion rates during last season. As you may guess and calculations confirm, a task that requires 45 repetitions per success for the best and reaches into the 100's for the worst is not just the product of random variation, there is a fairly considerable element of skill involved as well. One way of describing the spread of talent within the task is to calculate how many games we would need to watch before our impression of a team's talent at performing the task was more influenced by skill than random chance. In the case of scoring from crosses that happens after about 300 attempts or about 14 games for an average side.

The next assessment we need to make is how efficiently crosses use possession. My calculated average conversion rate for the first receiver to convert a cross from either open play or a set piece into a goal is once every 73 crosses. This doesn't look good, especially when compared to shots that are converted at a much higher rate. However, the cross is the precursor to the attempt on goal. If we are going to include crosses that sail harmlessly into the keeper's grasp in quantifying the potency of a cross, then we must also include the misplaced final third pass when quantifying the merits of a different approach that relies upon passes played towards the goal from areas other than the wings.

I therefore recorded the fate of all passes that were made into the final attacking third other than crosses for the 2011/12 EPL season. The comparison with crosses  is necessarily broad, but hopefully retains enough validity to compare an attack culminating in a cross and one based more around possession, passing and carving out an opening.

Regressed Number of Attempts Required To Score Once From A Cross and Once From A Final 3rd Pass.

Team.  Number of Crosses Needed To Score. No. of Final 3rd Passes Needed To Score.
Chelsea. 45 249
Norwich. 48 304
Man Utd. 49 167
Man City. 50 157
Blackburn. 65 260
Arsenal. 66 171
Everton. 74 267
Newcastle. 74 202
Stoke. 75 326
Aston Villa. 75 312
QPR. 78 331
Sunderland. 83 273
WBA. 90 252
Swansea. 92 246
Fulham. 94 227
Wigan. 94 331
Bolton. 96 253
Wolves. 99 363
Tottenham. 114 171
Liverpool. 139 341

If we repeat the previous analysis this time for chances made from passes into and inside the final third, we find that the average team attempts 135 such passes during a game. Again scoring from such passes is a skill and this should become apparent over the slightly shorter timescale of just ten games instead of the 14 for crosses. In terms of raw efficiency teams need to execute between 170 and 360 such passes to score one goal, with the average 240.

If we lastly include accuracy rates for each category of chance creation, crosses reached their intended target  23% of the time in 2011/12 compared to 66% of the time for final third passes.

We can therefore build up an identikit for our two classes of chance precursor. Scoring from either a cross or a final third pass are skills that vary between teams. A single cross has on average a greater goal threat than does a single final third pass, but ball retention is much more likely for the latter than the former. In essence we have for crosses a high risk, high reward skill compared to a predominately ground based passing strategy that is low risk, but also low reward for each individual pass.

Ballpark Figures For Goals From Both Crosses and From Final Third Passes, EPL 2011/12.

Crosses. Final 3rd
Average Number Per Game. 22 135
Number Needed To Score. 73 240
Accuracy. 23% 66%
% of Games Where Such An Assist Led To A Goal. 26% 39%
Total Goals From Such Passes. 2011/12. 230 429.

These are by necessity of the data just ball park figures, but if a team wanted to move from a balanced model of crosses and final third passes for chance creation towards a full on Barcelona approach, they might need to replace their 22 crosses per game with 72 extra final third passes.....just to stand still in goal expectancy terms. Of the 760 team appearances in last year's EPL 200+ final third passes was out of reach on 84% of those occasions.

A much more important question is whether both approaches are not needed to enhance a team's attacking capability in the complex interactions that comprise a football game. Crosses require taller, possibly less agile defenders to defend the ball. They may be more vulnerable if a team that possesses a crossing threat then also employs Barcelona type passing based attacks as well. 

NFL defenses must respect the less efficient pass (in possession retention terms) because teams do not commit totally to the more efficient run (in possession retention terms). They recognize the benefits of a mixed strategy, even if one of the ways of advancing the scoreboard is less efficient than another. Passing the football  and running the football both contribute significantly to scoring and the presence of one mode of attack may enhance the effectiveness of the other. Even the most potent of passing attacks in the NFL struggle when the scoreboard and time constraints force them to continually resort to a one dimensional passing attack.

Arsenal scored goals from final 3rd passes in half their games, but they also scored from crosses in a third of their matches. If they become one dimensional and dispense with crosses all together, will they become even more potent or even more predictable and easy to deal with ? Barca have wonderful, exciting and very expensive players, but even they failed to overcome Real Madrid in La Liga, Chelsea in the Champions League and Spain were held by both Italy and Portugal in regulation at the Euros. 

The very best exponents of passing based football have fallen short twice last season and Spain required a shootout along the way to the Final, maybe crossing isn't dead and it's all in the game theory.


  1. Thank you for this analysis, which, as you suggest, probably indicates that a varied approach is best. If the detailed data was available for a league such as the Mexican, for example, there may be a better opportunity to measure the effectiveness of a varied approach, as the teams who favour crosses stand out more, statistically, than in the EPL (Cruz Azul have made a total of 90 crosses in five matches thus far this season; the next highest total is 50).

    That said, I do believe there is an inherent flaw to this analysis: all final third passes are not necessarily attempting to produce a direct pass - or flow of passes - that will lead to a goal. Often, interchanges between full-back, winger and a third player in the final third will occur in order to try and manufacture a crossing position, for instance.

    I'm not sure what data you're working with and therefore am uncertain as to whether data of the requisite detail exists, or could even be analysed sufficiently, if it did, but you would need to filter out those final third passes not related to crafting a shot on goal - a minefield I know! Only then would we have an accurate picture of the number of final third passes required to score a goal.

    One final point. Do the statistics differentiate between low, medium height and head-height crosses? It would be interesting to see which is generally more effective, as the skill required to deliver each one accurately varies. For instance, a low cross from the byline drilled across the area for an incoming striker is probably better thought out, and has more chance of producing a goal, then a looping high cross, swung in from a deep area, that requires the striker to generate power in his header.

  2. Hi NickD85,
    totally agree with the final 3rd passes not always being the precursor to a ground attempt, but with the available data it's the best proxy I could come up with. Even if you transfer some final 3rd passes to the crossing tally, crosses should still be used, imo. Maybe when the play by play becomes available....

    I can't differentiate at the moment for type of cross, but it's a good point. Some corner analysis I've done suggests that corner placement (six yard box and inswinging) is a more effective policy than others and Delap's throws in his prime were certainly more effective when he threw them flat and at pace. Watching him set teams up with a couple of high looping deliveries before launching his money ball was always an amusing diversion at the Britannia.


  3. Hi Mark

    Thank you for your reply. I assumed there was probably a lack of detail in the available data to allow that distinction to be made, which seems to be the case.

    I agree with you that a varied approach is probably most effective, although its unfortunate us mere mortals don't have access to the wide range of data the Premier League clubs do in order to prove this more credibly.