One of the issues of the new forecast model is deciding which kind of shots to use to forecast player success: all of them, only those in the box or only those on target. Those on target have the best correlation to goals scored, however, there is a slight concern with limiting ourselves to that data alone. Consider the below example:
Robin van Persie: Appearances 10, Total Shots 55, 10 Shots On Target, 3 Goals
If we only look at his shots on target we see that he is averaging just one a game, with 30% of them hitting the back of the net. The issue is that he has historically hit the target at a much better rate than 10/55 (18%), having a success rate more in the 44% range. We therefore need to adjust for the fact that we believe 24 of his next 55 shots (44%) will hit the target and thus his expected goals will be higher.
We have some issue about how to generate this historic rate, especially with regards to what data to use, but for now I'm happy to look at such data for players like van Persie who have a proven history in the Premier League, even if in his case, it was with another team (someone like Berbatov, who has moved to a weaker team might be different).
The next issue is whether we should adjust the rate at which shots on target are converted into goals. This one is much less clear. If you look at the below table, it shows all the significant fantasy players and the rate at which their shots on target have become goals. If you look to the bottom of the table you will note an average conversion rate, and the colouring shows whether players are above/below that average. The keen eye will note that only five players (Balotelli, Berbatov, P Cisse, Fletcher and Nolan) have exceeded league average every year while only four (Bale, Fellaini, Santi Cazorla and Silva) have consistently been below average.
My (admittedly early) conclusion is that there is little reason to think that SoT conversion is consistent year on year and, frankly, is probably a combination of luck, strength of opponent 'keeper, and of course some skill. Issues like where shots are taken from, quality of teammate etc can also be factored in, but for now I'm happy to apply a standard league average rate to all players (probably split by midfielders/forwards once I run the actual numbers). So if you hit the target 10 times, we're going to give you credit for ~3 goals.
We wouldn't want to expand that rate to include defenders of course, or possibly even the league's weaker players, but given that we're really only looking at the top 100 or so attacking players, I'm comfortable that such a generalisation will do more good than harm (are you, for instance, ready to give Cisse a goal for 53% of all his SoTs, when so far this year that rate is 20%). As always I welcome any objections/suggestions below.
Robin van Persie: Appearances 10, Total Shots 55, 10 Shots On Target, 3 Goals
If we only look at his shots on target we see that he is averaging just one a game, with 30% of them hitting the back of the net. The issue is that he has historically hit the target at a much better rate than 10/55 (18%), having a success rate more in the 44% range. We therefore need to adjust for the fact that we believe 24 of his next 55 shots (44%) will hit the target and thus his expected goals will be higher.
We have some issue about how to generate this historic rate, especially with regards to what data to use, but for now I'm happy to look at such data for players like van Persie who have a proven history in the Premier League, even if in his case, it was with another team (someone like Berbatov, who has moved to a weaker team might be different).
The next issue is whether we should adjust the rate at which shots on target are converted into goals. This one is much less clear. If you look at the below table, it shows all the significant fantasy players and the rate at which their shots on target have become goals. If you look to the bottom of the table you will note an average conversion rate, and the colouring shows whether players are above/below that average. The keen eye will note that only five players (Balotelli, Berbatov, P Cisse, Fletcher and Nolan) have exceeded league average every year while only four (Bale, Fellaini, Santi Cazorla and Silva) have consistently been below average.
My (admittedly early) conclusion is that there is little reason to think that SoT conversion is consistent year on year and, frankly, is probably a combination of luck, strength of opponent 'keeper, and of course some skill. Issues like where shots are taken from, quality of teammate etc can also be factored in, but for now I'm happy to apply a standard league average rate to all players (probably split by midfielders/forwards once I run the actual numbers). So if you hit the target 10 times, we're going to give you credit for ~3 goals.
We wouldn't want to expand that rate to include defenders of course, or possibly even the league's weaker players, but given that we're really only looking at the top 100 or so attacking players, I'm comfortable that such a generalisation will do more good than harm (are you, for instance, ready to give Cisse a goal for 53% of all his SoTs, when so far this year that rate is 20%). As always I welcome any objections/suggestions below.
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