APBRmetrics

[Ben F.]

As brought up in the "How well would this team perform?" thread, I wonder about the validity of using assisted%, at least in small part, to find out how well someone can create their own relatively high percentage shot.

I think this would be something very interesting to look at, but really don't have a clue how to measure it. I don't think it should be done on a league-wide basis, but rather, on a player by player basis. I think there's something here, but I just can't quite put my finger on it. Hopefully you guys can help me out.

Let's take a look at Kobe Bryant, for example.

Year - Assisted% - FG% - eFG%

0203 - 40% - 45.1% - 48.2%
0304 - 47% - 44.1% - 47.1%
0405 - 30% - 42.6% - 46.7%

Personally, I think this can tell you something about Kobe. It seems that his eFG% has only taken a slight dip with the huge drop off in assisted%.

Now let's look at Dirk.

0203 - 66% - 46.3% - 51.4%
0304 - 72% - 46.2% - 50.0%
0405 - 53% - 45.2% - 48.4%

Dirk also had a huge drop off in assisted% this last year. In fact, his pattern followed about the same pattern as Kobe's over the last 3 years - bump up in asst'd%, then huge drop off, with a steadying decline in efficiency. Both are regarded as stars and have still been able to maintain a fairly efficient presence while creating more for themselves.

But now let's look at Richard Jefferson, who is clearly not on the same level as these two.

0203 - 68% - 50.1% - 50.4%
0304 - 70% - 49.8% - 52.1%
0405 - 54% - 42.2% - 44.9%

All these three players' assisted percentages dropped off by at least 15%. However, with the first two superstars, eFG% dropped by at most 1.6%. With Jefferson? 7.2%.

What I'm trying to say is that I think there's something there. I think you can come up with something similar to Dean's efficiency curves, player by player. Instead of usage, look at how often they are assisted.

I know there are problems with what I've presented above - different factors you could look at as to what the difference is between those players. But I still think that something can be taken out of this.
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XOHoops - A New Kind of Fantasy Basketball

[gabefarkas]

this is something i'm very interested in investigating further, but i'm not sure if there's enough data out there to accurately look at it.

specifically, i would love to be able to come up with a chart for each player that shows efficiency vs assisted% (with assisted% as the independent variable)....i guess this would be similar to Ch 19 of DeanO's book.

[Ben F.]

I'm looking at cutting up the play-by-plays and analyzing this on a game-by-game basis. Graphing Assisted% vs. 2pt-FG% and Assisted% vs. 3ptFG% per game, and trying to get a "skill curve" type readout from that.

2 things:
a) Do you think this would be worthwhile? Ways to improve this study?
b) Does anyone have an already written out list of the NBA schedule (in excel of some kind of format that I can cut up) so that I can easily get a list of links to the play-by-play?

Thanks for the help.
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XOHoops - A New Kind of Fantasy Basketball

[HoopStudies]

[Ed Küpfer]

[Ben F.]

Well, I can fairly easily write a parser to pick apart the play-by-play logs and find what I want - the difficulties lie in directing the parser to the right place.

I know that at least this year, the play-by-play on the NBA website is at the address of the following formula:

http://scores.nba.com/games/yyyymmdd/AwayTeamHomeTeam/PlayByPlayPrint.html

So the hard part that I was looking for help on was getting the schedule, so that I could have a list of games with their date to direct the parser to.

If you have the actual play-by-play logs from previous years, that would be great. Once again though, the schedule would be necessary (unless you have the files in a numbered order, or something) so that the parser would know the file name to go to.

If you can help with any of this, that would be great.

P.S. I would prefer the NBA logs, if you could e-mail them to FFSBasketball ]at[ gmail ]dot[ com. Thanks a bunch.
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XOHoops - A New Kind of Fantasy Basketball

[Ben F.]

Also, before embarking on this study, are there any suggestions of a better way to do it, or something to look into while doing it?
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XOHoops - A New Kind of Fantasy Basketball

[Ed Küpfer]

[Ben F.]

OK, well this is a slightly different approach to what I was thinking, but it might make more sense, because it's more general, which means there's more data possible.

The only problem with what you presented is how to record the data. Should it just be in a list, delimited by commas or something?

So a sample would be:
Time,Score,Assistee,type of shot,assister
3:40,33-40,Odom,Running Jump,Atkins

How exactly would this help? It would seem we're back with the same problem as in the play-by-plays. That information is right in the play-by-plays, the key is how to categorize it.

What I was going to do was for each player have a column in the database for assisted%, and one for FG%. Delimit each game in those columns by commas, then be able to paste it into excel and make a graph for anyone you want of their assisted% vs. FG%.

The parser could always be run again for 2ptFG%, 3ptFG%, eFG%, or whatever measure you wish.
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XOHoops - A New Kind of Fantasy Basketball

[Ed Küpfer]

[Ben F.]

There are many ways to get around excel, so that's not that big of a deal (for example, just rotate the table so columns become rows, and you can have unlimited rows - you can do this with Paste Special -> Transpose).

I think I'll do my original study first, see how it turns out, and then I'll edit the parser to take data that anyone else requests. That shouldn't be too hard. I'll let you know when I have results.
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XOHoops - A New Kind of Fantasy Basketball

[gabefarkas]

i had envisioned the same thing, where it's sort of like the skill curves. put assisted% on the x-axis, and efg% on the y-axis.

[Ben F.]

First off, thanks to Ed for the help.

Well, I got the parser working, and cut up the Hawks' PBPs from last year.

I'll post Terry's and Stephen Jackson's (added Reef, Sura and Ratliff) "skill curves" (we'll have to come up with another name), and you can take from them what you want.

The x-axis is assisted%, and the y-axis is FG% (straight, not eFG%).

Just a disclaimer: I compared my totals, and they look a little off of the actual NBA totals, so I'll investigate what the problem is later. For now though, they're pretty accurate.

Stephen Jackson


Jason Terry


Added in Shareef's 53 games with ATL:


More - Sura:


And Ratliff:


Obviously this is only 5 players, so it's hard to judge, but it seems to me you can take some general patterns from them.

All of the first three are relatively stable, and can create their own fairly good looks (I think this was somewhat expected with this caliber of player). But Reef and Jackson trend up slightly, suggesting they are still better set up by a passer, while Terry, as a PG, seems more comfortable creating his own shot, as he has a slight (very slight) downward trend.

Note: Terry's year-by-year data supports this finding - he's more efficient creating for himself. The last two years his ast'd% has been around 45%, and his FG% around 42%. This year, his ast'd% has gone down to about 35%, while his FG% has risen to over 50%.

As for the last 2, Sura is hard to judge, because of a fairly small sample size, and he's all over the place.

Ratliff is, as expected, trending upwards. His best looks are not set up by his moves, but by the passer.
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XOHoops - A New Kind of Fantasy Basketball

[S.K.]

Interesting stuff, FFS.

Are you making any allowances for offensive putbacks/tips? I would think that this would significantly affect the results for a guy like Ratliff - it would technically count as "creating" the shot, but reflects rebounding skill rather than shot creation ability.
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[S.K.]

Wait, that didn't make sense - you're trying to use assisted% only as an indicator. I should think things through before I post.

Well, anyway, I think it would be worthwhile to try subtracting 'tips' from the unassisted FG, since they'll never be assisted.
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No books - no articles - no website.
Just opinions.

Ill-informed opinions.