Saturday, February 1, 2014

What everyone is missing from their evaluation of playmakers (and football generally):

            If you could name the most desired trait a footballer could have right now, it would certainly be creativity. The recent sale of Mata to Manchester United, and the transfer of Ozil to Arsenal in the summer, proved that smart teams are desperate to improve their attacking play by creating more chances (or in United’s case, that desperate teams are smart to improve their attacking play). The impact of the signings is already being felt, with Ozil being hailed as the reason for the Gunners success this year and Mata being championed to turn around United’s season. This has also been fueled by the nascent football statistical community (of which I consider myself a member) promoting the use of shots on goal and key passes (passes that lead to a shot on goal), amongst other metrics, to evaluate players, instead of the pigheaded insistence of the old guard to rely on goals and assists. However, there is a great risk we may now be overrating these creative players, and the reason cuts to the heart of our understanding of football generally.
            As a City fan, I remember when Steven Ireland first broke into the first team under Stuart Pearce and I was really excited. For a team that was utterly lacking in creativity (and our record-tying fewest home goals in the 2006-07 season provided ample proof of that), it was a breath of fresh air. He would actually make forward passes and runs, really coming into his own under Sven, combining with Elano and Petrov, and jumping another level under Mark Hughes. He was voted City’s player of the season in 2009 and, despite some ridiculous behavior, it was deserved even in a team with Robinho, future captain Vincent Kompany, and Elano. I remember a commenter on the Manchester Evening News website saying at the time he didn’t rate him and I was shocked. The reason given? He gives the ball away too much.
            As most football fans probably know, Ireland never again hit the heights of that 2008-09 season. I’ve followed the rest of Steven Ireland’s career as an interested observer, always wondering if he would, but that commenter’s point remains true: he gives the ball away too easily. For every inspired pass, there would be two wayward ones. For every intelligent run, there would be two lazy ones. He never earned the trust of any manager since Mark Hughes, and will presumably follow Hughes when he jumps clubs yet again.
            Stephen Ireland’s career has a lesson for us: the creativity a player brings to a team needs to be paired with retention of the football. Think of each attempted defense-splitting pass as a risk. It can be successful and lead to a chance on goal, or it can be intercepted by the defense and lead to a counter-attack. Those players that consistently provide that successful final ball (David Silva, say) are going to be much more valuable than those who hit and hope. That is why the number of key passes, or even key passes per 90 minutes, is not sufficient to judge a player’s creativity.
The good thing is most intelligent people seem to realize this and try to factor in ball retention in some manner when evaluating players. Some people use passing percentage, but that total is inflated by safe, easy square passes. Case in point, Javi Garcia - who most City fans would consider the worst player to get regular minutes in the squad - has a passing percentage of 91%. Some would point to successful long ball percentage, or crossing percentage, or even forward pass percentage. However, none of these achieve the relatively simple task of balancing chance creation with ball retention. For those more mathematically inclined, the denominators don’t match up, as you are comparing a counting stat (key passes) with a rate stat (passing percentage). There’s also the fact that there are other ways to lose the ball besides passing, getting tackled being the most obvious.
The solution? Start counting turnovers! It is maddening in that this would be so easy to do, but the appropriate data is so hard to find (if somebody does regularly post it somewhere, please let me know). Every time a player misplaces a pass, gets tackled, or generally loses the ball and the other team recovers, it’s a turnover. Counting turnovers would allow you to directly compare them with key passes and find who is able to consistently create chances without giving the ball away. Simply divide the player’s assists by his turnovers (the assist/turnover ratio, for those of you familiar with the term from basketball) and you have a good, simple analysis of said player’s creative abilities.
This brings up a consistent problem in football analysis: there is no baseline for statistics. Football tends to reward counting stats: goals, assists, and now key passes. The more someone has, the better they are. Sometimes this is augmented by looking at how many a player has per game, or better yet per 90 minutes. But there is still no concerted effort to do better, which is all the sadder because other sports prove it is possible.
Football has been an insular world for quite some time. Due to its stature in world sport, it rarely feels the need to learn from the other games in the world (and when it does, it focuses on the wrong ones, like Baseball and American Football, which have little to nothing in common with it). Unfortunately, there is much other sports can bring to football, particularly in analysis of the game. In basketball for example, turnovers are measured and regarded as extremely important, and the assist/turnover ratio is an important indicator of a player’s creativity.
Another important insight from basketball is using the number of times a team has possession as a baseline for analysis. Thus rather than focusing on per-game totals, which can be inflated by style of play, you can focus on per-possession totals. This normalizes for the differences in how teams play and lets you compare individuals on different teams more easily. As with turnovers, this is something we can already measure, we just choose not to. Time of possession percentage is included in every football match report, all we have to do is count the number of times the ball changes hands rather than just total time each team has the ball.
Are creative players like Ozil and Mata overrated? Quite possibly. Ozil has had some important turnovers, most notably in the City game when he gave the ball away for Fernandinho’s first; Mata plays for United, so Q.E.D. he is probably overrated. Without the ability to look a little deeper into the stats, we can’t really know for sure. Measuring turnovers and possessions would be a huge step forward for statistical analysis in football and help us find who the best playmakers, and footballers, truly are.

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