Visualizing Expected Goals, Actual Goals, and Player Salary

If you have not heard of Expected Goals (xG) then please have a read of these posts before continuing. 

11tegen11 has written about expected goals (xG) and concluded that it predicts future performance better than other metrics such as Points Per Game (PPG), Goal Ratio, Shots Ratio & Shots on Target Ratio.

Using the interactive visualization, you can see how your favorite players performed each season and how much they earned per season. As you will notice, a number of players "over-perform" and others "under-perform" their xG every season. We could classify them as being "lucky" or "unlucky". Dan Altman in this video explains why this may or may not be the case.

See the interactive graphic after the jump.

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A thought on Big Data and Club Analysis

I talked a bit about Big vs. Small data last week--in case you missed it, go back and check it out--and we kind of talked about how you don't have to necessarily rely on the revolution of big data. There is a need to make do with what is currently available. However, while that big data is sometimes available, there are other encumbrances to deal with:

Beyond the complexity and time constraints placed on the analysis, another major obstacle faced in the job – like that faced by so many people entrusted with big data within an organisation, football club or otherwise – is to make data useful, accessible and engaging to colleagues who have little interest or experience in dealing with numbers.

This from a recent interview with Ben Smith of the development performance systems at Chelsea FC. A club that is often quoted as one of the "big-4" in the English Premier League. It's important to understand that, while many of these clubs have information at their disposal, few (if any) know or understand the practicality of implementing the information into their planning and preparation phase.

If fact, reading back on the 'Counter Attack' blog by Richard Whittal, some clubs--i.e. most--don't pay their club analysts. That should give you a brief, if not all together insulting, view of how much they respect the value of the service provided. I'm not saying they don't see it as useful in "some capacity", I just think that, in terms of how much they pay the rest of the staff, they could afford to have a full time analyst, especially for what an analyst has the potential to provide.

But it is not, of course, just the coaching and scouting staff that benefit from the big data analytics being carried out at the club, the players are also reaping the rewards of the work across the club. He says: “Every one of Chelsea’s Academy players from the age of nine has a personalised development programme."

There is some interesting stuff here to think about. It sounds a lot like how Ravi Ramineni has started helping out David Tenney, Sounders FC fitness coach, over the past 6-8 months.

By the way, h/t goes to Ravi who linked the article from his twitter.