Every City fan will recognize the importance of the Goal Difference (GD) statistic, as that very metric provided City their first title in the Premier League era in 2012. There’s a reason that GD is the second most important category in the League Table after points, as it reflects the total offensive and defensive performance of the club throughout the entirety of the season. Given the magnitude at the team level, it probably makes sense to look at individual goal difference for players when they are on the pitch. Who is on the pitch when City scores and who is on the pitch when City concedes? Anyone who follows ice hockey will recognize this as a player’s +/- rating, which is one of the major stat categories for individual players in that sport. While the stat makes more sense to track in a sport where players rotate on the field of play (ice) every 45 seconds, the concept easily translates to football at the player level.
In football, however, the stat cannot be evenly applied to all players because of actual playing time. How can you compare Pablo Zabaleta’s rating of +23 to Dedryk Boyata’s +3 rating? Let’s make an infograph, shall we, with individual player Goal Difference (+/-) plotted against full games (90s) played. Graph is not adjusted for 11 v 10 situations, strength of opponent, score effects, or any other metric – just straight Goal Difference. Take a look:
Reading the Graph
Fairly self-explanatory with both axes labeled and each player identified. Dark blue dots for defenders, medium blue for midfielders, and light blue for forwards…simple enough. The diagonal trendline represents City’s average Goal Difference per Game (currently at +33 after 33 matches-updated through West Ham) with the slightly larger dots reflecting the players with a better than club average +/- per 90 & the smaller dots reflecting those players with a +/- per 90 less than the average. As with any statistic, this graph should be used in conjunction with a whole vast array of other statistical metrics and categories in order to paint a complete picture about a player or the club in general. I’ll leave it up to the reader to draw their own conclusions from the visual (a few key observations first):
Yaya Toure & James Milner
Yaya has the best overall +/- rating of all City players (+27) – it’s obvious that goals happen when he is on the pitch. Milner’s +/- rating of +22 is even more impressive given that he has played almost 9 full matches less than Yaya. It begs the question, why doesn’t Milner play more if his presence on the pitch reflects in such positive output?
Clearly the negative outlier in the illustration, Fernandinho’s +/- rating isn’t pretty. I'm starting to get the impression that while Fernandinho passes the eyeball test when watching his play on the pitch, he fails in the statistical analysis of his play off the pitch (at least this season).
While the above chart is quite interesting, it certainly does not answer every question, nor does it tell the full story about a player. For those wishing to see City’s Players Individual Goal Difference broken down in other forms, good thing we have you covered below:
- Home Fixtures
- Away Fixtures
- 1st Half of Season
- 2nd Half of Season
- Against Arsenal / Chelsea / Liverpool / United
- Against Opponents in Top Half of the Table
- Against Opponents in Bottom Half of the Table
- 2013-2014 Season Equivalent Fixtures for Year over Year Comparisons