7 ms·

The "ghost" players in these animated replays that show where the system thinks a player should have been are fascinating to see. I wonder how automatic it is -

by mmc 14y ago

The "ghost" players in these animated replays that show where the system thinks a player should have been are fascinating to see. I wonder how automatic it is - if games could be analyzed like that without much expert input, this would be a really cool thing to have for recreational teams who want to get better but can't afford expert coaching. I'm thinking my late-night adult league hockey team would probably benefit from some replays like this.

swanson 14y ago
It would be interesting - though it will be some time before the price comes down. The cameras to do the tracking cost $100k/year at the moment.
- mmc 14y ago
  $100k/year is certainly a lot :) I can imagine facilities like hockey rinks buying the cameras and selling the service to the teams that play there, but not at that price. My impression of hockey rinks is that they're not terribly profitable. Most of the ones I've played in seem like borderline charities.
- eumenides1 14y ago
  While I agree 100K is alot, it's nothing compared to salary and cap space. To be able to spend money outside of cap restictions to imporove your team is a stragetic advantage. I don't think the price will come down, the only people who need it are wealthy and the wealthy can't afford to not have it.
streptomycin 14y ago
I'd be pretty curious about that too. I actually tried doing something semi-similar before. My goal was to simulate a basketball game by having every player take an action based on "expected points per possession". So if you are covered tightly but a shooter is open, your expected points would be high for passing but low for shooting. This would then be done recursively for every decision, continuously looking ahead until the shot clock expires (so maybe the best move would be to pass it into the post, draw a double team, and then kick it out for an open shot). The obvious problem was that there are a ton of free parameters involved and tons of branching. Every little action creates a new branch of possibilities with its own set of probability distributions. So even if (as they describe in the article) helping out more often decreases the likelihood of the current ball handler making a shot, how does that propagate through the rest of the possession?
- abecedarius 14y ago
  http://en.wikipedia.org/wiki/Markov_decision_process http://en.wikipedia.org/wiki/Markov_decision_process for a start.
the_watcher 14y ago
Unfortunately the cameras are pricey enough that only 15 of 30 NBA teams have purchased them, not to mention the half decade of work it took the Raptors to build the code to actually generate the visualizations. Maybe someday it will be commercially available and affordable, but that day seems a long way off to me.
- nickalewis 14y ago
  I don't think it's the cost that's keeping other NBA Teams from purchasing ($100K/year is pennies to an NBA franchise). I suspect its more of a front-office vs coaching thing. Adopting this as part of a teams core prep takes education; Effectively learning how to understand this type of data and apply it in practice over the course of a season.
  - the_watcher 14y ago
    It should be pennies to an NBA franchise (when they are spending millions on players who don't play). Unfortunately, owners like Robert Sarver and Donald Sterling are notorious for refusing to spend on marginal upgrades like a quality visitors locker room, or a a full support staff. Even Paul Allen has a reputation for refusing to pay for a high quality training staff in Portland - probably a bit undeserved since he seems to spend on other important things and I can't imagine why training staff would be something he ignores. Also, there is a floor for player salaries that must be met. The analytics vs. coaching issue is a real one too, but don't discount owners being cheap.
- ssharp 14y ago
  I'm wondering why the 15 other teams aren't on board yet. If the price is only 100k, it's nothing to an NBA team. If those other 15 teams don't already have an advanced analytics team in place, then it makes sense not to have the camera until you have a structure in place to make sure of the camera data. It will be interesting with this huge push in basketball over the past couple years to see where this type of analysis leads. The NBA model right now is pretty simple: get two or three superstars, align them with solid role players, and play in championships. It's hard to imagine analytics pushing a team like Houston to be able to beat a team like Miami or Oklahoma City in a seven-game series because the talent gap is so substantial. Houston can play a smarter game but the other teams still function better. What I could see happening, however, if a team like Oklahoma City, while slightly less talented than Miami, can implement insights from this analysis to raise their EV, it might overcome the slightly smaller talent gap. Even in that small sense, it makes more to spend a couple million a year on analytics than it does to pay an average NBA player several million. Since the NBA has both a salary cap and maximum contracts, it pushes the price of an average play up quite a bit, so better value may be had by raising the effectiveness of your current talent than trying to bring in new players.
JoelSutherland 14y ago
It sounds like there probably wouldn't be enough data to generate the ghost players. According to the article they depend on the skills of the individual covers. (i.e. Player X is a 35% three point shooter so don't leave him in the corner to help on a cut) The 82-game NBA schedule really helps to generate large enough sample sizes about players. I could see it being potentially possible to just use average data, but if your rec league is anything like mine, talent ranges from a guy can credibly fake a three and then dunk after one dribble to guys that can barely get up and down the court.

by mmc 14y ago

swanson 14y ago

It would be interesting - though it will be some time before the price comes down. The cameras to do the tracking cost $100k/year at the moment.

mmc 14y ago
$100k/year is certainly a lot :) I can imagine facilities like hockey rinks buying the cameras and selling the service to the teams that play there, but not at that price. My impression of hockey rinks is that they're not terribly profitable. Most of the ones I've played in seem like borderline charities.
eumenides1 14y ago
While I agree 100K is alot, it's nothing compared to salary and cap space. To be able to spend money outside of cap restictions to imporove your team is a stragetic advantage. I don't think the price will come down, the only people who need it are wealthy and the wealthy can't afford to not have it.

streptomycin 14y ago

I'd be pretty curious about that too. I actually tried doing something semi-similar before. My goal was to simulate a basketball game by having every player take an action based on "expected points per possession". So if you are covered tightly but a shooter is open, your expected points would be high for passing but low for shooting. This would then be done recursively for every decision, continuously looking ahead until the shot clock expires (so maybe the best move would be to pass it into the post, draw a double team, and then kick it out for an open shot). The obvious problem was that there are a ton of free parameters involved and tons of branching. Every little action creates a new branch of possibilities with its own set of probability distributions. So even if (as they describe in the article) helping out more often decreases the likelihood of the current ball handler making a shot, how does that propagate through the rest of the possession?

abecedarius 14y ago
http://en.wikipedia.org/wiki/Markov_decision_process http://en.wikipedia.org/wiki/Markov_decision_process for a start.

the_watcher 14y ago

Unfortunately the cameras are pricey enough that only 15 of 30 NBA teams have purchased them, not to mention the half decade of work it took the Raptors to build the code to actually generate the visualizations. Maybe someday it will be commercially available and affordable, but that day seems a long way off to me.

nickalewis 14y ago
I don't think it's the cost that's keeping other NBA Teams from purchasing ($100K/year is pennies to an NBA franchise). I suspect its more of a front-office vs coaching thing. Adopting this as part of a teams core prep takes education; Effectively learning how to understand this type of data and apply it in practice over the course of a season.
- the_watcher 14y ago
  It should be pennies to an NBA franchise (when they are spending millions on players who don't play). Unfortunately, owners like Robert Sarver and Donald Sterling are notorious for refusing to spend on marginal upgrades like a quality visitors locker room, or a a full support staff. Even Paul Allen has a reputation for refusing to pay for a high quality training staff in Portland - probably a bit undeserved since he seems to spend on other important things and I can't imagine why training staff would be something he ignores. Also, there is a floor for player salaries that must be met. The analytics vs. coaching issue is a real one too, but don't discount owners being cheap.
ssharp 14y ago
I'm wondering why the 15 other teams aren't on board yet. If the price is only 100k, it's nothing to an NBA team. If those other 15 teams don't already have an advanced analytics team in place, then it makes sense not to have the camera until you have a structure in place to make sure of the camera data. It will be interesting with this huge push in basketball over the past couple years to see where this type of analysis leads. The NBA model right now is pretty simple: get two or three superstars, align them with solid role players, and play in championships. It's hard to imagine analytics pushing a team like Houston to be able to beat a team like Miami or Oklahoma City in a seven-game series because the talent gap is so substantial. Houston can play a smarter game but the other teams still function better. What I could see happening, however, if a team like Oklahoma City, while slightly less talented than Miami, can implement insights from this analysis to raise their EV, it might overcome the slightly smaller talent gap. Even in that small sense, it makes more to spend a couple million a year on analytics than it does to pay an average NBA player several million. Since the NBA has both a salary cap and maximum contracts, it pushes the price of an average play up quite a bit, so better value may be had by raising the effectiveness of your current talent than trying to bring in new players.

JoelSutherland 14y ago

It sounds like there probably wouldn't be enough data to generate the ghost players. According to the article they depend on the skills of the individual covers. (i.e. Player X is a 35% three point shooter so don't leave him in the corner to help on a cut) The 82-game NBA schedule really helps to generate large enough sample sizes about players. I could see it being potentially possible to just use average data, but if your rec league is anything like mine, talent ranges from a guy can credibly fake a three and then dunk after one dribble to guys that can barely get up and down the court.