This document discusses factors that may influence a baseball team's performance compared to its expected win percentage based on run differential. It finds that relief pitcher performance, as measured by FIP, impacts a team's ability to outperform or underperform its run differential. The addition of managerial decisions shows defensive substitutions increase the likelihood of outperforming, while more pitchouts decrease it. Overall, the document aims to determine non-random reasons teams outperform or underperform expected win percentage based on run differential.
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1. Why Does a Team Outperform
its Run Differential?
Greg Ackerman
Syracuse University Sabermetrics Club
2. SU Sabermetrics Club
SABR Student Group Affiliate
Justin Mattingly
Joey Weinberg
Colby Conetta
Ray Garzia
Mallory Miller
Zack Potter
Marcus Shelmidine
Brandon Love
Matt Tanenbaum
Bryan Kilmeade
Justin Moritz
Stephen Marciello
Kyle OConnor
Willie Kniesner
Michael Rotondo
Matt Russo
Sam Fortier
Matt Filippi
Isaac Nelson
Zack Albright
John Van Ermen
Colton Smith
Chris Karasinski
Zach Tornabene
3. Basic Premise
Explain the Difference between Actual Win Percentage and Expected Win Percentage based on Run
Differential (Expected Win Percentage based upon Pythagenpat formula from run differential)
X = ((runs scored + runs against)/games)^.285
If achieve run differential to possibly put team in playoffs do not want to squander it
If borderline run differential for playoffs could be difference in attaining playoff spot
Will focus on 3 key factors that may influence teams outperforming or underperforming their run differential
Performance of Bench
Relief Pitching
Pitching Depth
Part II Add managerial decisions to the model
Pinch Hitters Used
Defensive Substitutions
Relievers Used
Etc.
4. Charts
Average of (Actual Win % - Expected Win %)
Standard Deviation of (Actual Win % - Expected Win %)
Variables calculated from www.baseball-reference.com
Team Examples of Difference in Actual Win % - Expected Win %
San Francisco Giants
St. Louis Cardinals
New York Yankees
Toronto Blue Jays
Colorado Rockies
12. Measures of Bench (Hitters) Performance
OPS+ - On-Base Average plus Slugging Percentage Adjusted for Park and
League
HR Home Runs
SB Stolen Bases
CS Caught Stealing
Calculated from Baseball Reference using only bench players listed for
each team weighted average based upon plate appearances of each
player
Ultimately, only included OPS+
Other variables did not add statistical value to the regression model beyond OPS+
13. Measure of Relief/Depth Pitcher Performance
FIP Fielding Independent Pitching
ERA+ - Earned Run Average adjusted for ballpark
SO/W strike out to walk ratio
Calculated as a weighted average based upon innings pitched
Calculated for group of relievers noted on Baseball-Reference includes
closer and top 4 used relievers
Calculated for group of depth pitchers noted on Baseball Reference-
includes pitchers not included in starters or relievers categories
14. Regression Model I
After different regression model incarnations settled upon the
following to illustrate results:
(Actual Expected Win %)i = 留0 +硫1 (Bench OPS+) + 硫2 (Relief variable)
+ 硫3 (Pitching Depth variable) + 竜i
15. Regression Results (Actual Win% - Pyth
Win%) on Bench and Relief Pitching
Performance
I II III
Intercept
0.0206
(1.4307)
Intercept
0.0071
(0.5750)
Intercept
-0.0102
(-1.0729)
OPS+ - Bench
0.00001
(0.1104)
OPS+ - Bench
0.00002
(0.1911)
OPS+ - Bench
0.00002
(0.1795)
FIP Relief
-0.0044**
(-1.9130)
ERA Relief
-0.0026
(-1.5358)
KBB Relief
0.0014
(1.3735)
FIP Depth
-0.0009
(-0.4956)
ERA Depth
0.0001
(0.0756)
KBB Depth
0.0007
(0.7328)
16. Results
Variables have expected signs for bench (hitter) performance, relief
pitching, and pitching depth
Only statistically significant result is for relief pitching performance
Specifically FIP
FIP has a negative and significant impact on (Actual Win Percentage
Exp. Win Percentage)
As FIP increases has negative impact on dependent variable
More likely to underperform run differential
As FIP decreases has positive impact on dependent variable
More likely to outperform run differential
17. Sample Bench OPS+ Relief FIP Depth FIP
top 10% Seasons -
Outperform Run Diff
81.56304 3.66215 4.691264
Bottom 10% Seasons -
Underperform Run Diff
81.63799 3.981814 4.769715
% Differential Between
Samples
-0.09% -8.03% -1.64%
20. Managerial Decisions
For Next Step: Added Managerial Decisions to the Data Set
To measure managerial decisions used the Bill James Handbook
Attempt to measure the impact of various managerial decisions on
the ability to outperform (underperform) a teams run differential
24. Results
Two statistically significant managerial variables:
Defensive Substitutions (+) significant at the 1% level
Pitchouts Ordered (-) significant at the 5% level
Defensive Substitutions more defensive substitutions used greater
likelihood to outperform run differential
Part is managerial decision
Part is roster flexibility
Pitchouts Ordered more pitchouts ordered greater likelihood to
underperform run differential
Part is wasting a pitch
Part is lack of faith in catcher/pitcher
Likely a proxy for risk averse behavior on part of manager
25. Results
Relief Pitcher Innings Pitched (-) but not quite statistically significant
(15% level)
When Managerial Statistics included impact of FIP-Relievers is
lessened as well no longer statistically significant
Tried including one or the other not quite statistically significant
Appears to still have some marginal effect on ability to
outperform/underperform run differential
30. Conclusions
Aimed to determine why teams outperform/underperform run differential
Is it just luck? or are there factors that contribute to its explanation?
Without Manager Data it appears that Relief Pitcher Performance
(measured by FIP) plays an important role
Increase in FIP by Relievers more likely to underperform
Decrease in FIP by Relievers more likely to outperform
With Manager Data
Defensive Substitutions more defensive subs more likely to outperform
Pitchouts likely proxy for risk aversion (poor catching performance?) more
pitchouts more likely to underperform run differential
Starting point of our research hope to learn more in future open to
different variables/approaches to help determine answers
Editor's Notes
#4: We are not looking at starting pitching and starting lineup, rather we are looking at performance of bench, relief pitching, and pitching depth.
#6: Talk about the Yankees, Giants, and Cardinals having high averages and have been outperforming their run differential between 2000 and 2013, while teams like the Blue Jays, Rockies, and
#7: One interesting thing here is that the Giants have the lowest standard deviation between 2000 and 2013
#8: 0 is what we would expect, so the Giants have regularly outperformed their run differential
#13: The key to this is that we used a weighted average for each team amongst bench hitters only, according to baseball-reference. We are really only going to be focusing on OPS+ because it is the most promising of the bench statistics.
#14: This is a weighted average of FIP, ERA+, and SO/BBW. We used
#15: The dependent variable here is actual expected win percentage. The independent variables are bench OPS+, and a variable amongst FIP, ERA, or strikeout to walk ratio amongst the top five relievers and depth pitching.
#16: These are all very small numbers because we are dealing with trying to explain a very small number, which is the difference between actual and expected win percentage.
#17: This makes sense because if you are not pitching well in late innings, you are likely to underperform your run differential, while if you have good Fielding Independent Pitching amongst relievers, they are more likely to outperform their run differential.
#18: This slide shows the best seasons and worst seasons in terms of outperforming and overperforming run differential. The only place we have a sizeable difference between the top 10% and bottom 10% of seasons is in relief FIP, as there is a 8.03% dropoff.
#19: This just gives an idea of the average bench OPS+ amongst the team.
#20: This is the difference between relief and depth FIP.