D
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I've done some more work refining my model for player involvement so that reflects where runs take place rather than just how many metres they ran. I've also had some discussions with members about incorporating other parts of players' games into the model. I've now done that. There is now a very small weighting for positive and negative plays both in attack and defence.
Note that this model uses the nrl.com stats for "tackles" and "missed tackle" but no other stats sources is used. Everything except tackles is captured by me.
As an off-season project, I'm going to start with round 1 and work my way through the season. I've also tried to boil everything within the game down to something that could be shown in one graphic. I'll add final details for each player once done.
To start, I thought it might be useful to provide a guide for how to read/interpret the information.
I'm going to use Oregon Kaufusi's Round 1 performance to demonstrate.
Attack vs Defence
This maps a player's attacking involvement against their defensive involvement.
* Closer to the top = more work running the ball
* Closer to the right = more tackling
The lines at 150 are a guide to represent a baseline for what you might expect from a middle-of-the-road bench forward in a game where the possession is 50/50.
* 150 in attack = half a game, 6 runs outside your own 40, no errors
* 150 in defence = half a game, 26 tackle, 0 misses
Anything more a player does will make one of his scores go up. Any errors, missed tackles, etc. will make one of his scores go down.
His round 1 graph shows us that compared to the 150+150 baseline, he was heavily involved in attack, with an OK level of involvement in defence.
Involvement vs Ball in Play
This maps a player's total involvement (attack plus defence score above) against their minutes. I've used "Ball in Play" here, because it is much more meaningful than "minutes", especially for low-minute players. There is ~55 minutes of Ball in Play in an NRL game, so 27.5 minutes is "half a game".
Again we have our baseline here.
* 150 attack + 150 defence = 300
* 27.5 minutes of ball in play.
This gives us some context around player usage vs their involvement. i.e. the Royce Hunt effect. If a player is going full noise for 20 minutes it is expected that they would be more heavily involved than a player who is out there for 50.
Again we see that Kaufusi in this game had a decent level of involvement, which he maintained for close to half a game.
Attacking Contribution
This one shows us how the player achieved their attacking score.
Kaufusi's attacking score was 300.
* 50 from kick returns
* 0 from runs inside his own 20
* 100 from runs inside his own 40
* 150 from runs outside his own 40
This gives us an idea of where and how he is contributing to gaining a yardage. Is he waiting at the 40m line for the backs to get to him, is he taking carries, is he getting his numbers pumped up by taking a bunch of kick returns, etc.? I've temporarily added Talakai in to this one to show the difference in the nature of how and where players contribute on yardage.
Also a note here... for forwards I am tracking all runs, but for backs I am only tracking yardage runs.
All in all for this game, this is a reasonable contribution from Kaufusi. Better than the baseline, and comparable overall to the work rate of the best metre-eating outside back.
Yardage Runs Pie Charts
This one is a cumulative version of the above, for all players combined. This tells us who is taking the runs in areas of the field.
Below we can see that for the whole team in this game, close to 3/4 of the runs from inside their own 20m line were from outside backs, and that once they got outside the 20 we saw a lot more involvement from the middles.
* The chart on the left is runs that start inside the 20m line.
* Note that the one on the right is runs that start on or outside the 20m line, but inside the 40m line.
I'll post Round 1 now
Note that this model uses the nrl.com stats for "tackles" and "missed tackle" but no other stats sources is used. Everything except tackles is captured by me.
As an off-season project, I'm going to start with round 1 and work my way through the season. I've also tried to boil everything within the game down to something that could be shown in one graphic. I'll add final details for each player once done.
To start, I thought it might be useful to provide a guide for how to read/interpret the information.
I'm going to use Oregon Kaufusi's Round 1 performance to demonstrate.
Attack vs Defence
This maps a player's attacking involvement against their defensive involvement.
* Closer to the top = more work running the ball
* Closer to the right = more tackling
The lines at 150 are a guide to represent a baseline for what you might expect from a middle-of-the-road bench forward in a game where the possession is 50/50.
* 150 in attack = half a game, 6 runs outside your own 40, no errors
* 150 in defence = half a game, 26 tackle, 0 misses
Anything more a player does will make one of his scores go up. Any errors, missed tackles, etc. will make one of his scores go down.
His round 1 graph shows us that compared to the 150+150 baseline, he was heavily involved in attack, with an OK level of involvement in defence.
Involvement vs Ball in Play
This maps a player's total involvement (attack plus defence score above) against their minutes. I've used "Ball in Play" here, because it is much more meaningful than "minutes", especially for low-minute players. There is ~55 minutes of Ball in Play in an NRL game, so 27.5 minutes is "half a game".
Again we have our baseline here.
* 150 attack + 150 defence = 300
* 27.5 minutes of ball in play.
This gives us some context around player usage vs their involvement. i.e. the Royce Hunt effect. If a player is going full noise for 20 minutes it is expected that they would be more heavily involved than a player who is out there for 50.
Again we see that Kaufusi in this game had a decent level of involvement, which he maintained for close to half a game.
Attacking Contribution
This one shows us how the player achieved their attacking score.
Kaufusi's attacking score was 300.
* 50 from kick returns
* 0 from runs inside his own 20
* 100 from runs inside his own 40
* 150 from runs outside his own 40
This gives us an idea of where and how he is contributing to gaining a yardage. Is he waiting at the 40m line for the backs to get to him, is he taking carries, is he getting his numbers pumped up by taking a bunch of kick returns, etc.? I've temporarily added Talakai in to this one to show the difference in the nature of how and where players contribute on yardage.
Also a note here... for forwards I am tracking all runs, but for backs I am only tracking yardage runs.
All in all for this game, this is a reasonable contribution from Kaufusi. Better than the baseline, and comparable overall to the work rate of the best metre-eating outside back.
Yardage Runs Pie Charts
This one is a cumulative version of the above, for all players combined. This tells us who is taking the runs in areas of the field.
Below we can see that for the whole team in this game, close to 3/4 of the runs from inside their own 20m line were from outside backs, and that once they got outside the 20 we saw a lot more involvement from the middles.
* The chart on the left is runs that start inside the 20m line.
* Note that the one on the right is runs that start on or outside the 20m line, but inside the 40m line.
I'll post Round 1 now
