Introducing a new and improved pBB%+ (Batters)

Yesterday, I gave an overview on the improved version of hitter pwOBAcon+. In the month of April, I reintroduced four pitching stats (pwOBAcon+, pBB%+, pK%+, and pwOBA+). In this piece, I will be talking about hitter pBB%+.

There are five variables: strike percent plus^2, contact percent plus^2, shadow percent plus^2, chase swing percent plus, and walk percent plus^2.

As I did for pitcher pBB%+, I tried my best to exclude pitches that resulted in catcher interference, a sacrifice bunt, a missed bunt, a bunt foul-tip, a foul bunt, a swinging pitchout, or a foul pitchout when it was convenient to do so. Additionally, I removed all pitches thrown in plate appearances that ended in a bunt. I excluded pitchouts and intentional balls as well.

Here are the lowest single-season strike percent plus marks since 2015

1. Joey Votto 2015 (87.8)
2. Alex Bregman 2019 (88.6)
3. Carlos Santana 2015 (89.0)
4. Matt Joyce 2016 (89.2)
5. Mike Trout 2019 (89.8)
6. Carlos Santana 2019 (90.0)
7. Joey Votto 2018 (90.2)
8. Alex Avila 2015 (90.3)
9. Carlos Santana 2020 (90.3)
10. Russell Martin 2018 (90.6)

Highest

1. José Iglesias 2019 (112.2)
2. R.A. Dickey 2017 (112.0)
3. Byron Buxton 2020 (111.2)
4. John Hicks 2019 (110.8)
5. Jorge Alfaro 2018 (110.8)
6. Kevin Pillar 2019 (110.6)
7. Hanser Alberto 2020 (110.3)
8. Pedro Ciriaco 2015 (110.3)
9. Victor Reyes 2018 (110.3)
10. Hanser Alberto 2019 (110.2)

Here are the lowest single-season contact percent plus marks since 2015

1. Joey Gallo 2015 (77.1)
2. Joey Gallo 2017 (77.6)
3. Noah Syndergaard 2019 (78.2)
4. Noah Syndergaard 2018 (78.3)
5. Keon Broxton 2019 (79.6)
6. Mike Foltynewicz 2018 (79.7)
7. Sandy Alcantara 2019 (79.8)
8. Kyle Freeland 2018 (79.8)
9. Jorge Alfaro 2018 (80.0)
10. Tyler O’Neill 2018 (80.3)

Highest

1. Luis Arraez 2019 (120.1)
2. David Fletcher 2019 (119.1)
3. Michael Brantley 2019 (117.8)
4. Joe Panik 2019 (117.8)
5. David Fletcher 2020 (117.7)
6. Willians Astudillo 2019 (116.7)
7. Eric Sogard 2019 (116.5)
8. Michael Brantley 2018 (116.4)
9. Nick Markakis 2018 (116.4)
10. Michael Brantley 2015 (116.4)

Here are the lowest single-season shadow percent plus marks since 2015

1. Bryce Harper 2015 (96.6)
2. Giancarlo Stanton 2018 (97.5)
3. Nolan Arenado 2019 (97.7)
4. Javier Báez 2018 (97.8)
5. Mark Trumbo 2017 (98.0)
6. Brett Lawrie 2015 (98.1)
7. Brandon Phillips 2017 (98.1)
8. Giancarlo Stanton 2016 (98.1)
9. Kendrys Morales 2016 (98.1)
10. Gary Sánchez 2017 (98.2)

Highest

1. Matt Carpenter 2017 (102.8)
2. Billy Hamilton 2017 (102.3)
3. Anthony Rendon 2018 (102.1)
4. Neil Walker 2017 (102.1)
5. Tommy Pham 2017 (101.9)
6. Cameron Maybin 2015 (101.9)
7. Starlin Castro 2019 (101.9)
8. Danny Valencia 2017 (101.8)
9. Andrew McCutchen 2019 (101.7)
10. Jake Lamb 2016 (101.7)

Here are the lowest single-season chase swing percent plus marks since 2015

1. Joey Votto 2018 (37.1)
2. Joey Votto 2017 (40.4)
3. Cavan Biggio 2019 (43.7)
4. Logan Forsythe 2019 (43.7)
5. Russell Martin 2018 (44.7)
6. Joey Votto 2015 (45.8)
7. Robbie Grossman 2019 (46.4)
8. Tommy Pham 2019 (46.7)
9. Brandon Nimmo 2017 (47.2)
10. Matt Joyce 2016 (47.5)

Highest

1. Hanser Alberto 2020 (194.1)
2. Jorge Alfaro 2019 (185.8)
3. Salvador Perez 2017 (174.3)
4. José Iglesias 2019 (173.9)
5. Ronny Rodríguez 2019 (173.8)
6. Salvador Perez 2018 (173.1)
7. Pablo Sandoval 2015 (172.4)
8. John Hicks 2019 (170.0)
9. Kevin Pillar 2019 (168.2)
10. Victor Reyes 2018 (168.1)

Here are the lowest single-season walk percent plus marks since 2015

1. Dee Strange-Gordon 2018 (37.9)
2. Salvador Perez 2015 (41.2)
3. Kevin Pillar 2019 (42.3)
4. Tim Anderson 2017 (42.9)
5. Jean Segura 2015 (43.2)
6. Alcides Escobar 2017 (43.5)
7. Omar Infante 2015 (47.5)
8. Scooter Gennett 2015 (48.3)
9. Brandon Phillips 2016 (48.7)
10. Hanser Alberto 2019 (49.5)

Highest

1. Joey Votto 2015 (227.8)
2. Bryce Harper 2015 (206.9)
3. José Bautista 2015 (199.1)
4. Aaron Judge 2017 (191.0)
5. Matt Joyce 2016 (191.0)
6. Carlos Santana 2015 (187.2)
7. Bryce Harper 2018 (186.6)
8. Alex Bregman 2019 (186.2)
9. Matt Carpenter 2017 (186.2)
10. José Bautista 2016 (186.1)

pBB%+ comes from a linear regression where strike percent plus^2, contact percent plus^2, shadow percent plus^2, chase swing percent plus, and walk percent plus^2 in season n were the x-variables and non-adjusted (not regressed) walk percent plus in season n+1 was the y-variable. A hitter’s pBB%+ value is what one would predict that hitters’s non-adjusted walk percent plus to be the following season given that hitter’s strike percent plus^2, contact percent plus^2, shadow percent plus^2, chase swing percent plus, and walk percent plus^2.

Increases in strike percent plus, contact percent plus, and chase swing percent plus in season n are associated with a decrease in non-adjusted walk percent plus in season n+1. This makes sense, as more strikes should mean fewer walks, more contact could mean more balls in play, and it’s impatient to swing in the chase zone.

In contrast, increases in shadow percent plus and walk percent plus in season n are associated with an increase in non-adjusted walk percent plus in season n+1. Hitters that see more pitches in the shadow zone might be better hitters whom pitchers want to pitch around. More walks in the present corresponding to more walks moving forward is to be expected.

Here are the lowest single-season predictive walk percent plus marks since 2015

1. José Iglesias 2019 (20.1)
2. Kevin Pillar 2019 (26.7)
3. Hanser Alberto 2019 (26.7)
4. Hanser Alberto 2020 (27.8)
5. R.A. Dickey 2017 (28.8)
6. Ronald Torreyes 2017 (35.2)
7. Victor Reyes 2018 (35.6)
8. Salvador Perez 2017 (37.0)
9. Byron Buxton 2020 (37.5)
10. John Hicks 2019 (39.6)

Highest

1. Joey Votto 2015 (222.6)
2. Matt Joyce 2016 (196.1)
3. Alex Avila 2015 (188.6)
4. Carlos Santana 2015 (186.0)
5. Matt Carpenter 2017 (185.9)
6. Aaron Judge 2018 (182.4)
7. José Bautista 2015 (181.1)
8. Alex Bregman 2019 (179.9)
9. Alex Avila 2017 (179.9)
10. Alex Avila 2016 (179.2)

My model was built off of consecutive player-seasons of at least 300 plate appearances from 2015-2018 (n = 638).

In looking at how predictive 2018 pBB% was of 2019 BB% compared to 2018 BB%, one can see that pBB% is more year-to-year than BB% is. When it comes to predicting future walk rate, predictive walk percent is more predictive of future walk rate than walk rate is.

If one wants a better idea of how often one can expect a batter to walk in a future season, one should look at that batter’s pBB%+.

Featured image- Federal Baseball