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WNBA Player Impact Estimate leaders

 
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tfan



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PostPosted: 06/24/18 4:48 am    ::: WNBA Player Impact Estimate leaders Reply Reply with quote

as of 06/23/2018 all-stars based on PIE (Games, MPG):

1) Dearica Hamby (14, 12.9) 21.5
2) Liz Cambage (11,30.4) 20.2
3) Elena Delle Donne (9, 29.0) 20.0
4) Candace Parker (9, 27.6) 19.8
5) Sylvia Fowles (12, 32.5) 18.5
6) Angel McCoughtry (13, 29.9) 18.1
7) Brittney Griner (14, 33.6) 17.4
8 ) Nneka Ogwumike (12, 30.9) 17.4
9) Breanna Stewart (13, 32.5) 17.3
10) Cheyenne Parker (12, 21.8 ) 16.6
11) A'ja Wilson (14, 31.4) 16.2
12) Kayla Alexander (11, 9.4) 15.7
13) Diana Taurasi (14, 31.4) 15.3
14) Skylar Diggins-Smith (11, 34.7) 15.3
15) Tina Charles (11, 33.6) 15.3
16) Chelsea Gray (12, 31.4) 14.8
17) Glory Johnson (6, 21.7) 14.8
18 ) Tiffany Hayes (11 , 30.0) 14.8
19 ) Natasha Howard (13, 27.4) 14.7
20) Jewell Loyd (13, 30.6) 14.7
21) Chiney Ogwumike (11 28.8 ) 14.5
22) Natalie Achonwa (13 ,23.9) 13.9
23) Cecelia Zandalasini (8, 12.5) 13.8
24) DeWanna Bonner (14, 32.2) 13.4

eliminating the 3 players [Hamby, Alexander and Zandalasini] who play only a quarter or less of the game adds:


25) LaToya Sanders (8, 19.2) 13.2
26) Alyssa Thomas (9, 31.1) 13.1
27) Maya Moore (12, 34.0) 12.9

Make it a requirement that you have to average at least 26 minutes a game and the rest of the non-star names except Natasha Howard [Parker, Achonwa, Sanders] are eliminated along with Glory Johnson, and added are:

28 ) Candace Dupree (11, 30.1) 12.5
29) Courtney Williams (12, 26.6) 12.1
30) Kia Nurse (11, 26.2) 11.8
31) Jasmine Thomas (12, 26.9) 11.4


ClayK



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PostPosted: 06/24/18 9:58 am    ::: Reply Reply with quote

Good list: What's the formula?



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root_thing



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PostPosted: 06/24/18 1:24 pm    ::: Reply Reply with quote

Quote:
PIE
Name: Player Impact Estimate
Definition: PIE measures a player's overall statistical contribution against the total statistics in games they play in. PIE yields results which are comparable to other advanced statistics (e.g. PER) using a simple formula.

Formula (PTS + FGM + FTM - FGA - FTA + DREB + (.5 * OREB) + AST + STL + (.5 * BLK) - PF - TO) / (GmPTS + GmFGM + GmFTM - GmFGA - GmFTA + GmDREB + (.5 * GmOREB) + GmAST + GmSTL + (.5 * GmBLK) - GmPF - GmTO)


The main point of PIE is that by comparing individual statistics to combined game statistics for both teams, you build in an adjustment for pace and efficiency. Someone who plays for a defense-oriented team will often find herself in low pace, low efficiency, low scoring games that depress her statistics. Conversely, a player on an offense-oriented team will participate in a lot of barnburners where it's easier to put up gaudy numbers. PIE makes an attempt to adjust for these differences.



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ClayK



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PostPosted: 06/24/18 8:11 pm    ::: Reply Reply with quote

Almost completely based on offense, which is the flaw in most of these. And blocked shots, like steals, aren't even necessarily a good measure of defensive impact.



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Randy



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PostPosted: 06/24/18 10:19 pm    ::: Reply Reply with quote

It is telling that a block has a weighting of .5 meaning its value is only half that of a defensive rebound or a steal which have a weighting of one. This makes sense because a steal, represents a possession while a block frequently ends with in the opposing team's hands anyway. Brittany Griner get 3.1 blocks per game which are worth less in the PIE formula than Gabby Williams' 1.8 steals per game.

What doesn't make a lot of sense to me in the formula is that an offensive rebound is only given a weight of .5, even though, it too represents another possession of the ball the same as a defensive rebound or a steal.

To improve the formula, I would suggest they start tracking deflections as they are probably worth nearly as much as a block.


root_thing



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PostPosted: 06/24/18 10:30 pm    ::: Reply Reply with quote

ClayK wrote:
Almost completely based on offense, which is the flaw in most of these. And blocked shots, like steals, aren't even necessarily a good measure of defensive impact.


True, but we're nowhere near what they have in MLB where sabermetrics guys or some computer program is deciding what should occur on every play. I was watching a game the other day, and as Aaron Judge was chasing a fly ball toward the line, they flashed a live changing probability of him making the catch. When he did, the counter stopped at 43%. I have no idea how that was done. Maybe they have a program calculating the trajectory, where the ball is likely to land, and how far the fielder has to run. In basketball, a whole bunch of variables would need to be considered to assess good defense -- like where the offensive player received the ball, whether or not there's a height mismatch, how far the closest help defenders are, whether an effective screen was set, whether the correct switch was made, etc. As far as I can tell, the WNBA is lucky if the official scorer just gets all the standard stats right. For instance, I've seen games where I'm pretty sure they didn't count a block or two, and I've seen other games where they appeared overly generous when crediting assists. So, I'll take what I can get. PIE seems like a step up from PER.



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Richyyy



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PostPosted: 06/24/18 10:53 pm    ::: Reply Reply with quote

Baseball's easier because so much of it is essentially individualised. It's a bunch of singular athletic acts within a vaguely team framework, whereas basketball is a true team sport. And defense gets even more complicated. Whether Judge makes that catch and whether Taurasi makes a shot are yes or no plays with a somewhat quantifiable percentages if you have enough data, but unless you know exactly what a team's defensive scheme is you often don't know who screwed up. And blame is often shared on some level as well. Maybe Player A got beat off the dribble, but maybe Player B was too slow to help and Player C was too far off their man which meant Player A had to angle themselves differently to start with. Maybe the defender did what looked like a nice job sliding over a screen and staying on a player's hip - but the scheme and the scouting report said he/she should've gone under and offered that player the jump shot because they're greedy and not as good of a shooter as they think they are.

Most of baseball is did you hit/catch/throw/whatever the ball when you were given the chance to? Recent years have shown you can go into a hell of a lot of depth on those numbers, but the game's made for it, unlike basketball defense.



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tfan



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PostPosted: 06/24/18 11:20 pm    ::: Reply Reply with quote

Randy wrote:


What doesn't make a lot of sense to me in the formula is that an offensive rebound is only given a weight of .5, even though, it too represents another possession of the ball the same as a defensive rebound or a steal.


I don't get that either. When I saw it my first thought was of a post player missing a chippy and then grabbing their own rebound (sometimes twice in a row). But that can't be that high a percentage of all offensive rebounds. And even in that situation, the player already gets dinged for the missed shot.


root_thing



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PostPosted: 06/25/18 12:20 am    ::: Reply Reply with quote

tfan wrote:
Randy wrote:


What doesn't make a lot of sense to me in the formula is that an offensive rebound is only given a weight of .5, even though, it too represents another possession of the ball the same as a defensive rebound or a steal.


I don't get that either. When I saw it my first thought was of a post player missing a chippy and then grabbing their own rebound (sometimes twice in a row). But that can't be that high a percentage of all offensive rebounds. And even in that situation, the player already gets dinged for the missed shot.


Apparently, a lot of coaches feel that chasing offensive rebounds means you're not getting back on defense. Supposedly, there have been studies that show a strong correlation between wins and defensive rebounds, but not so much with O-Boards. We've actually had this discussion about the Tulsa Shock/Dallas Wings franchise which has been at or near the top for offensive rebounds while being in the bottom two for defense. Are the two things related? Anyway, here's a pretty good discussion from 2016 which examines the decline in importance of offensive rebounding:

http://www.espn.com/nba/story/_/id/14505051/transition-defense-left-offensive-rebounds-cutting-room-floor



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Randy



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PostPosted: 06/25/18 7:24 am    ::: Reply Reply with quote

I think it is true that the teams have learned that putting too much effort into crashing the boards means they aren't getting back on D. So teams are unwise to have several players going for ORs. However, that doesn't negate the value of a single OR. Once you have the ball - getting back on D is not the issue.


root_thing



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PostPosted: 06/25/18 12:42 pm    ::: Reply Reply with quote

Randy wrote:
I think it is true that the teams have learned that putting too much effort into crashing the boards means they aren't getting back on D. So teams are unwise to have several players going for ORs. However, that doesn't negate the value of a single OR. Once you have the ball - getting back on D is not the issue.


I don't disagree, but just guessing at the possible rationale, they are either deducting an implied cost for pursuing the offensive rebound or they are simply trying to devalue the offensive rebound vis-à-vis the defensive rebound. What the imputed difference in value should be is a matter of debate. I'm not convinced a whole lot of research went into that 50% weighting. Maybe the adjustment shouldn't be a deduction from the O-board but rather an enhancement to the defensive rebound. Perhaps the D-board should have a coefficient larger than 1.0. You can go in a lot of directions with this.

Looking at another calculation, PER gives assists a 2/3 weighting. I guess the logic is that some of the credit should go to the scorer for making the basket. However, from what I've seen in decades of watching basketball, it's more likely that the recipient of a pass screws-up the assist rather than aids it. How many times have you seen a player catch a perfect kick-out pass, but then turn down the shot? Or how many times have you seen someone take a perfect pass and then miss the layup? As far as I'm concerned, people should get extra credit for an assist to make up for all the times their teammates ruined the opportunity. Razz



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Randy



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PostPosted: 06/25/18 1:20 pm    ::: Reply Reply with quote

I forget - in the case the recipient drops the pass - do they get the TO, or is it the passer?

As for assists, I suppose one argument against full weighting for an assist would be that you would be giving 3 points for one 2 point basket. However, that's not particularly compelling. In the end, I agree the numbers in the formula were probably not selected on any rigorous basis, but rather a subjective notion as to the relative importance of each one of the items included.

It does seem that the PIE formula already favors frontcourt players over backcourt players and posts in particular (11 of the first 12). The first guard to appear on the ranking is Taurasi at 13. So maybe the full weighting of the assist and derating of the OR was to level the playing field between guards and the frontcourt players. Who knows?


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PostPosted: 06/25/18 3:07 pm    ::: Reply Reply with quote

Randy wrote:
I forget - in the case the recipient drops the pass - do they get the TO, or is it the passer?

Judgement call based on whose fault it is, essentially.



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root_thing



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PostPosted: 06/25/18 3:12 pm    ::: Reply Reply with quote

All these combination stats: PIE, PER, EFF, seem to favor frontcourt players. People playing closer to the basket tend to shoot higher percentages, and it's easier to get a rebound than an assist. Pass-first point guards usually have the lowest ratings.



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