Erroneous action types for 3pt shots

Question

Erroneous action types for 3pt shots

Closed this issue 2 years ago · 17 comments

More just for awareness, but some (~20-30) of the records in the "shots" data frame have an action_type of "3pt" when their location puts them well inside the 3pt-line. All instances are missed shots so likely operator error. Just an FYI.

Answer 1 · 2021-12-02T07:29:59.000Z

thanks @davescroggs !! i'm finding some other errors too now that i'm starting to analyse the data rather than make tibbles with it... 🚨

Answer 2 · 2021-12-08T03:44:05.000Z

g'day @davescroggs - could you help me with this? i'm trying to figure out how to isolate the records that are erroneous. how would you suggest identifying xy locations that fall within the 3pt shot arc?

Answer 3 · 2021-12-08T07:14:33.000Z

Hey @jacquietran I found it by calculating the distance from the centre of the ring and finding any shots that were less than 6.75m and tagged as 3pt. I also plotted them to check they weren't corner 3's too, and from memory none of them were. Code for shot distance below.

shots %>%
mutate(x = x / 100 * 28,
y = y / 100 * 15,
shot_dist = sqrt((x - 1.6)^2 + (y - 7.5)^2 ))

Answer 4 · 2021-12-18T18:52:36.000Z

Kia ora @davescroggs - ahh I see! Thanks for the help! I'll tidy this up today 😸

Answer 5 · 2021-12-18T19:51:04.000Z

Taking a closer look using data from games played before today 2021-12-19 (i.e., including games from the 2021 season that is in progress).

# Load libraries
library(tidyverse)
library(ggplot2)
library(ggforce)

# 
shots %>%
	mutate(
		x_for_halfcourt_plot = if_else(x > 50, 100 - x, x),
		x_adj_halfcourt = x_for_halfcourt_plot / 100 * 28,
                y_adj = y / 100 * 15,
		shot_dist = sqrt((x_adj_halfcourt - 1.6)^2 + (y_adj - 7.5)^2 )) %>%
	filter(action_type == "3pt") %>%
	filter(shot_dist < 6.75) %>%
	mutate(
                # Categorisation allowing for small degree of human error when coding 3-pt attempt locations
		shot_category = case_when(
                        # Recorded location is erroneous when shot distance < 6 m from ring
			shot_dist < 6   ~ "erroneous",
                        # Recorded location is accepted when shot distance >= 6 m from ring
			shot_dist >= 6 ~ "accepted")) %>%
	arrange(
		desc(shot_dist)
	) -> short_3pt_shots

# Set court features
add_forward_goal_circle <- function() geom_arc_bar(
	aes(x0 = 50, y0 = 200, r0 = 0, r = 4.9/0.1525,
			start = pi / 2, end = 3 / 2 * pi),
	inherit.aes = FALSE)
add_key <- function() geom_rect(
	xmin = 0, xmax = 5.8, ymin = 9.95, ymax = 5.05, col = "black", fill = NA)
add_3pt_arc <- function() geom_arc(
	aes(x0 = 1.575, y0 = 7.5, r = 6.75,
			start = pi - 0.1862454, end = 0.1862454),
	col = "black", inherit.aes = FALSE)
add_halfcourt <- function() geom_rect(
	xmin = 0, xmax = 14, ymin = 0, ymax = 15, col = "black",
	fill = NA, inherit.aes = FALSE)
add_top_key <- function() geom_arc(
	aes(x0 = 5.8, y0 = 7.5, r = 1.8, start = pi, end = 0),
	col = "black", inherit.aes = FALSE)
add_backboard <- function() geom_segment(
	aes(x = 1.2, xend = 1.2, y = 6.6, yend = 8.4), col = "black")
add_basket <- function() geom_circle(
	aes(x0 = 1.675, y0 = 7.5, r = 0.45/2), col = "black", fill = NA,
	inherit.aes = FALSE)
add_centre_circle <- function() geom_arc(
	aes(x0 = 14, y0 = 7.5, r = 1.8, start = pi, end = 2*pi),
	col = "black", inherit.aes = FALSE)
add_3ball_segment1 <- function() geom_segment(
	aes(x = 0, xend = 2.825, y = 0.9, yend = 0.9), inherit.aes = FALSE)
add_3ball_segment2 <- function() geom_segment(
	aes(x = 0, xend = 2.825, y = 14.1, yend = 14.1), inherit.aes = FALSE)

# Plot
p <- ggplot(
	short_3pt_shots, aes(x = x_adj_halfcourt, y = y_adj))
p <- p + add_key()
p <- p + add_top_key()
p <- p + add_halfcourt()
p <- p + add_backboard()
p <- p + add_basket()
p <- p + add_3ball_segment1()
p <- p + add_3ball_segment2()
p <- p + add_3pt_arc()
p <- p + add_centre_circle()
p <- p + geom_point(
	aes(colour = shot_category),
	stat = "identity", size = 3, alpha = 0.5)
p <- p + scale_colour_manual(
	values = c(
		"accepted" = "dodgerblue",
		"erroneous" = "red"))
p <- p + coord_fixed(xlim = c(0,14), ylim = c(0,15))
p <- p + facet_wrap(~season, nrow = 2)
p <- p + theme_void()

Answer 6 · 2021-12-18T20:00:17.000Z

Observations

Leave the 2016 data as is.
Check for available game vision corresponding to the games with erroneous shot locations and recode, either by:
- Recoding the XY location of the shot (and retaining action_type == "3pt")
- Recoding the action_type to "2pt" (and retaining the XY location as recorded)
Where there is no game video that can be used for cross-checking, and the data is inconclusive, then leave it as is.
There is erroneous shot location data recorded as recently as the current season (which is only in Round 3). Maybe need to set up some data quality monitoring to detect errors in future?

Answer 7 · 2021-12-18T20:11:13.000Z

Looking only at the 3-pt shot locations I have categorised as "erroneous" (allowing for some human error in specifying XY location)

short_3pt_shots_erroneous <- short_3pt_shots %>%
	filter(shot_category == "erroneous")

# Plot
p <- ggplot(
	short_3pt_shots_erroneous, aes(x = x_adj_halfcourt, y = y_adj))
p <- p + add_key()
p <- p + add_top_key()
p <- p + add_halfcourt()
p <- p + add_backboard()
p <- p + add_basket()
p <- p + add_3ball_segment1()
p <- p + add_3ball_segment2()
p <- p + add_3pt_arc()
p <- p + add_centre_circle()
p <- p + geom_point(
	colour = "red", stat = "identity", size = 3, alpha = 0.5)
p <- p + coord_fixed(xlim = c(0,14), ylim = c(0,15))
p <- p + facet_wrap(~season, nrow = 2)
p <- p + theme_void()

short_3pt_shots_erroneous %>%
	select(
		season, page_id, action_number, team_name, team_name_opp,
		shot_result, x, y, x_adj_halfcourt, y_adj, shot_dist, scoreboard_name) %>%
	arrange(desc(season), desc(shot_dist)) %>%
	gt::gt()

Answer 8 · 2021-12-18T20:36:40.000Z

WNBL: 2021 / 2022

page_id = 2061074, action_number = 631

link to live stats: page_id = 2061074
action_number: 631
originally recorded as: 3-pt shot missed by Lauren Scherf
actual shot: 2-pt shot missed by Lauren Scherf
corroborated by: https://www.youtube.com/watch?v=schN1XVwvsQ

page_id = 2061074, action_number = 642

link to live stats: page_id = 2061074
action_number: 642
originally recorded as: 3-pt shot missed by Brittany Sykes
actual shot: 2-pt shot missed by Brittany Sykes
corroborated by: https://www.youtube.com/watch?v=schN1XVwvsQ

page_id = 1997422

link to live stats: page_id = 1997422
action_number: 635
originally recorded as: 3-pt shot missed by Sara Blicavs
actual shot: 2-pt shot missed by Sara Blicavs
corroborated by: video - https://youtu.be/KV_2nJLOWqM?t=4000

data tidying to do for all of the above:

in shots and pbp data, update shot type to "2pt"
in shots, keep XY location as is
in box_scores and box_scores_detailed, adjust two pointers attempted and % and three pointers attempted and %

Note: In my checking process, I looked through the pbp data as well and there may be some issues potentially with the action numbers - they might not always be in chronological order??? Will investigate further and open a separate issue about this if needed.

Answer 9 · 2021-12-18T22:03:51.000Z

2020

page_id = 1777499

link to live stats: page_id = 1777499
action_number: 151
originally recorded as: 3-pt shot missed by Stella Beck
actual shot: not verified
no data tidying to do at this stage; shot location is at the top of the key so it could have been a 3-pt attempt with location incorrectly recorded, but not possible to know without more info / game video

Couldn't find video of the full game (maybe accessible via Kayo as VOD, but I don't have a subscription). Videos online (on Youtube and Facebook) are highlight reels only and do not include this particular shot, taken at the end of the 1st quarter.

Answer 10 · 2021-12-19T00:36:01.000Z

2019

page_id = 1330488

link to live stats: page_id = 1330488
action_number: 260
originally recorded as: 3-pt shot missed by Mercedes Russell
actual shot: not verified
data tidying to do, given XY location is very close to the ring and Mercedes Russell is a Centre who does not shoot 3s (as per her WNBA stats):
- in shots and pbp data, update shot type to "2pt"
- in shots, keep XY location as is
- in box_scores and box_scores_detailed, adjust two pointers attempted and % and three pointers attempted and %

Couldn't find video of the full game (maybe accessible via Kayo as VOD, but I don't have a subscription).

Answer 11 · 2021-12-19T00:55:26.000Z

2018

page_id = 1087577

link to live stats: page_id = 1087577
action_number: 277
originally recorded as: 3-pt shot missed by Lauren Nicholson
actual shot: not verified
data tidying to do, given XY location is inside the key:
- in shots and pbp data, update shot type to "2pt"
- in shots, keep XY location as is
- in box_scores and box_scores_detailed, adjust two pointers attempted and % and three pointers attempted and %

Couldn't find video of the full game.

Answer 12 · 2021-12-19T00:57:54.000Z

2017

page_id == 681961

link to live stats: page_id = 681961
action_number: 193
originally recorded as: 3-pt shot missed by Vanessa Panousis
actual shot: not verified
no data tidying to do at this stage: shot location is at the elbow; the marker is well inside the 3-pt line but Panousis does shoot 3s so more info / game video is required to verify shot type.

page_id == 681927

link to live stats: page_id = 681927
action_number: 262
originally recorded as: 3-pt shot missed by Mikhaela Donnelly
actual shot: not verified - only relevant video i could find is this highlights reel which does not include this particular shot
no data tidying to do at this stage: shot location marker is well inside the 3-pt line but Donnelly does shoot 3s so more info / game video is required to verify shot type.

Very short shot distances

There are a set of distances recorded with action_type == "3pt" but are quite close to the ring. All of these shots have an XY location that is < 2 m from the ring:

page_id == 681947, action_number == 61 (M. Bass)
page_id == 681956, action_number == 235 (S. Greaves)
page_id == 681958, action_number == 107 (T. Roberts)
page_id == 681958, action_number == 188 (K. Pedersen)
page_id == 681958, action_number == 319 (C. Williams)
page_id == 681960, action_number == 79 (A. Wehrung)
page_id == 681968, action_number == 397 (A. Kunek)
page_id == 681974, action_number == 306 (L. Scherf)
page_id == 681974, action_number == 359 (D. Garbin)
page_id == 681977, action_number == 307 (A. Taylor)

For each of the above, data tidying to do:

in shots and pbp data, update shot type to "2pt"
in shots, keep XY location as is
in box_scores and box_scores_detailed, adjust two pointers attempted and % and three pointers attempted and %

Answer 13 · 2021-12-19T00:57:59.000Z

2015

page_id == 137266

link to live stats: page_id = 137266
action_number: 208
originally recorded as: 3-pt shot missed by Rachel Jarry
actual shot: not verified
no data tidying to do at this stage: shot location marker is well inside the 3-pt line but Jarry does shoot 3s so more info / game video is required to verify shot type.

page_id == 137248

link to live stats: page_id = 137248
action_number: 471
originally recorded as: 3-pt shot missed by Louella Tomlinson
actual shot: not verified
no data tidying to do at this stage: shot location marker is well inside the 3-pt line but Tomlinson does shoot 3s so more info / game video is required to verify shot type.

Very short shot distances

These shots have an XY location that is < 2 m from the ring:

page_id == 137261, action_number == 394 (A. Bishop)
page_id == 137309, action_number == 398 (K. Ebzery)

For each of the above, data tidying to do:

in shots and pbp data, update shot type to "2pt"
in shots, keep XY location as is
in box_scores and box_scores_detailed, adjust two pointers attempted and % and three pointers attempted and %

Answer 14 · 2021-12-19T01:02:57.000Z

2014

page_id = 64536

link to live stats: page_id = 64536
action_number: 460
originally recorded as: 3-pt shot missed by Maddie Garrick
actual shot: not verified
no data tidying to do at this stage: shot location marker is well inside the 3-pt line but Garrick does shoot 3s so more info / game video is required to verify shot type.

Short shot distances

These shots have an XY location that is inside the key:

page_id == 64580, action_number == 219 (S. Greaves)
page_id == 64597, action_number == 454 (S. Batkovic)

For each of the above, data tidying to do:

in shots and pbp data, update shot type to "2pt"
in shots, keep XY location as is
in box_scores and box_scores_detailed, adjust two pointers attempted and % and three pointers attempted and %

Answer 15 · 2021-12-19T07:33:13.000Z

summarising the checks above:

or simpler, focusing on shots to be updated only:

short_3pt_shots_erroneous %>%
	select(
		season, page_id, action_number, team_name, team_name_opp, shot_dist,
		scoreboard_name) %>%
	arrange(desc(season), desc(shot_dist)) %>%
	mutate(
		to_be_updated = case_when(
			page_id %in% c(
				1997422,
				1330488,
				1087577,
				681947,
				681956,
				681960,
				681968,
				681977,
				137261,
				137309,
				64580,
				64597)               ~ TRUE,
			page_id == 681958 &
				action_number == 107 ~ TRUE,
			page_id == 681958 &
				action_number == 188 ~ TRUE,
			page_id == 681958 &
				action_number == 319 ~ TRUE,
			page_id == 681974 &
				action_number == 306 ~ TRUE,
			page_id == 681974 &
				action_number == 359 ~ TRUE,
			TRUE                   ~ FALSE)) %>%
	filter(to_be_updated == TRUE) %>%
	gt::gt()

For each of the shots listed in the screenshot immediately above, data tidying to do:

in shots and pbp data, update shot type to "2pt"
in shots, keep XY location as is
in box_scores and box_scores_detailed, adjust two pointers attempted and % and three pointers attempted and %

Answer 16 · 2022-07-30T23:41:45.000Z

^ oops, that last commit message was meant to read "in 2017 games"

Answer 17 · 2022-07-31T03:08:00.000Z

This will be ready to close when the beta branch of {wnblr} is merged.