Baseball Player Won-Loss Records
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Component 8: Baserunner Outs

In the eighth step of calculating Player Wins and Losses, batters, baserunners, and fielders are given credit and blame for baserunning outs. Components 8 and 9 are the only two components for which pitchers receive no credit. Instead, the ability to throw out baserunners and/or allow/prevent baserunner advancement (Component 9) are attributed entirely to the fielders responsible for the play(s).

1.    Calculation of Component 8 Player Game Points
Component 8 doles out credits/debits for whether any baserunners (including the batter) are thrown out on the bases. Ground-ball double plays are not included here – those are measured in Component 7. As with most other components, players are credited for baserunner outs as well as for avoiding (failing to make) baserunner outs, so that the overall Component 8 winning percentage is 0.500. Component 8 Player decisions are allocated to any baserunner on third base first, followed by any baserunner on second, followed by any baserunner on first, then, finally by the batter.

2.    Impact of the Batter on Baserunner Outs
Component 8 Player Games are shared between batters and baserunners based on the extent to which player winning percentages persist across different sample periods. The mathematics underlying this division is described elsewhere.

To summarize, one measure of the extent to which a particular factor is a skill is the extent to which a player’s winning percentage persists over time. To evaluate the persistence of skills, I fit a simple persistence equation which modeled Component 8 winning percentage on even-numbered plays as a function of Component 8 winning percentage on odd-numbered plays:

(Component 8 Win Pct)Even = b•(Component 8 Win Pct)Odd + (1-b)•(WinPct)Baseline

where (WinPct)Baseline represents a baseline winning percentage toward which Component 8 winning percentages regress over time.

Equations of this type were fit for Component 8 Player Game Points for batters and baserunners. Separate equations were estimated for each starting base for baserunners. The results for these equations are shown below. A brief explanation of these variables follows.

The number n is the number of players over whom the equation was estimated, that is, who accumulated any Player wins and/or losses on both odd- and even-numbered plays. The value R2 measures the percentage of variation in the dependent variable (WinPctEven) explained by the equation (i.e., explained by WinPctOdd). The numbers in parentheses are t-statistics. T-statistics measure the significance of b, that is, the confidence we have that b is greater than zero. The greater the t-statistic, the more confident we are that the true value of b is greater than zero. Roughly speaking, if the t-statistic is greater than 2, then we can be at least 95% certain that the true value of b is greater than zero (assuming that certain statistical assumptions regarding our model hold). The value of (WinPct)Baseline, the baseline winning percentage toward which winning percentages regress over time, is set equal to 0.500 by construction.
note: To be precise, I estimate unique Persistence Equations for every season, which use all of my data in all of these equations, but weight the data based on how close to the season of interest it is. The equations shown here weight each season equally.
Persistence of Component 8 Winning Percentage: Baserunner on First Base
 
Batters:  n = 56,887, R2 = 0.0000


WinPctEven = (38.12%)*WinPctOdd + (61.88%)*0.5000
                (100.9)                              



 
Baserunners:  n = 58,292, R2 = 0.0000


WinPctEven = (41.59%)*WinPctOdd + (58.41%)*0.5000
                (107.0)
The persistence of Component 8.1 decisions is extremely similar for batters (38.1%) and baserunners (41.6%). Component 8.1 player decisions are divided 47.8% to batters and 52.2% to baserunners.

Persistence of Component 8 Winning Percentage: Baserunner on Second Base
 
Batters:  n = 53,372, R2 = 0.0000


WinPctEven = (53.33%)*WinPctOdd + (46.67%)*0.5000
                (145.7)                              



 
Baserunners:  n = 52,550, R2 = 0.0000


WinPctEven = (37.40%)*WinPctOdd + (62.60%)*0.5000
                (89.92)
Component 8.2 decisions are divided 58.8% to batters and 41.2% to baserunners.

Persistence of Component 8 Winning Percentage: Baserunner on Third Base
 
Batters:  n = 43,716, R2 = 0.0000


WinPctEven = (82.45%)*WinPctOdd + (17.55%)*0.5000
                (297.1)                              



 
Baserunners:  n = 42,003, R2 = 0.0000


WinPctEven = (73.33%)*WinPctOdd + (26.67%)*0.5000
                (219.2)
Component 8.3 decisions are divided 52.9% to batters and 47.1% to baserunners.

Components 8 and 9 are somewhat negatively correlated. Fielders with strong throwing arms may, for example, have relatively low assist totals if runners are afraid to try to take extra bases against them. Baserunners who are more aggressive are more likely both to advance an extra base (Component 9 wins) but also to make outs on the bases. The relationship of Components 8 and 9 is explored in a separate article.

Component 8 leaders can be found here.

All articles are written so that they pull data directly from the most recent version of the Player won-lost database. Hence, any numbers cited within these articles should automatically incorporate the most recent update to Player won-lost records. In some cases, however, the accompanying text may have been written based on previous versions of Player won-lost records. I apologize if this results in non-sensical text in any cases.

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