**Component 7: Ground-Ball Double Plays**

Component 7 comes into play when ground-ball outs are recorded in double-play situations – defined as a runner on first base and fewer than two outs. Offensive Component 7 games are split between the batter and the baserunner on first base. Defensive Component 7 games are split between pitchers and fielders. Fielding Component 7 games are split between the fielder who starts the initial play and the potential pivot man on the double play.1. Calculation of Component 7 Player Game Points

Component 7 Player Games are shared between batters and baserunners, and between pitchers and fielders based on the extent to which player winning percentages persist across different sample periods. The mathematics underlying this division is described elsewhere.2. Division of Component 7 Game Points Between Pitchers and Fielders

For Component 7, decisions allocated to fielders are split evenly between the fielder who starts the initial play and the pivot man. In the latter case (the pivot man), such a fielder only receives Component 7 credit/blame if he is involved in the play. That is, on a ground ball to the shortstop, if the baserunner on first is forced out, 6-4, then the second baseman would be considered the pivot man in this case and would share some Component 7 credit/blame based on whether he was able to complete the 6-4-3 double play. If, however, the shortstop simply threw directly to first for the 6-3 out, then all blame for failing to turn the double play in that case would fall on the shortstop.

To summarize the process for dividing Player decisions, 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 7 winning percentage on even-numbered plays as a function of Component 7 winning percentage on odd-numbered plays:

(Component 7 Win Pct)_{Even} = b•(Component 7 Win Pct)_{Odd} + (1-b)•(WinPct)_{Baseline}

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 R

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 7 Winning Percentage: Catcher

Pitchers: n = 1,425, R^{2}= 0.0005

WinPct_{Even}= (10.20%)•WinPct_{Odd}+ (89.80%)•0.5000 (3.780)

Catchers: n = 2,290, R^{2}= -0.0171

WinPct_{Even}= (4.04%)•WinPct_{Odd}+ (95.96%)•0.5000 (1.729)

Component 7 winning percentage is considerably more persistent for pitchers than for catchers. This leads to a split of Component 7.2 decisions of
71.6% to pitchers and
28.4% to catchers.

Persistence of Component 7 Winning Percentage: First Basemen

Pitchers: n = 20,334, R^{2}= -0.3450

WinPct_{Even}= (86.54%)•WinPct_{Odd}+ (13.46%)•0.5000 (238.5)

First Basemen: n = 6,044, R^{2}= -0.1522

WinPct_{Even}= (44.59%)•WinPct_{Odd}+ (55.41%)•0.5000 (39.38)

As with catchers, the persistence coefficient here is stronger for pitchers than for fielders. The Component 7.3 decision splits are
66.0% to pitchers versus
34.0% to first basemen in this case.

Persistence of Component 7 Winning Percentage: Second Basemen

Pitchers: n = 25,779, R^{2}= 0.0001

WinPct_{Even}= (-1.17%)•WinPct_{Odd}+ (101.17%)•0.5000 (-1.903)

Second Basemen: n = 6,935, R^{2}= 0.0436

WinPct_{Even}= (21.59%)•WinPct_{Odd}+ (78.41%)•0.5000 (18.72)

Unlike with catchers and corner infielders, Component 7 winning percentages are more persistent for second basemen than for pitchers. Based on these results, Component 7.4 Player decisions are divided
-5.7% to pitchers versus
105.7% to second basemen.

Overall, Component 7 accounts for 17.1% of all fielding decisions by second basemen.

Overall, Component 7 accounts for 17.1% of all fielding decisions by second basemen.

Persistence of Component 7 Winning Percentage: Third Basemen

Pitchers: n = 2,199, R^{2}= -0.1269

WinPct_{Even}= (0.65%)•WinPct_{Odd}+ (99.35%)•0.5000 (0.272)

Third Basemen: n = 2,519, R^{2}= -0.0369

WinPct_{Even}= (-0.63%)•WinPct_{Odd}+ (100.63%)•0.5000 (-0.321)

The split of Component 7 decisions for third basemen is similar to that of first basemen, with third basemen receiving
-2,885.5% of the credit for double plays in which they are involved.

Persistence of Component 7 Winning Percentage: Shortstops

Pitchers: n = 22,762, R^{2}= -0.0021

WinPct_{Even}= (-1.49%)•WinPct_{Odd}+ (101.49%)•0.5000 (-2.220)

Shortstops: n = 5,757, R^{2}= 0.0251

WinPct_{Even}= (17.37%)•WinPct_{Odd}+ (82.63%)•0.5000 (13.69)

As with second basemen, Component 7.6 player decisions are credited more heavily to shortstops than to pitchers. Component 7.6 Player decisions are divided
-9.4% to pitchers versus
109.4% to shortstops.

Component 7 is a somewhat less important component of shortstop defense than for second basemen, accounting for only 13.6% of all fielding decisions by shortstops.

Component 7 is a somewhat less important component of shortstop defense than for second basemen, accounting for only 13.6% of all fielding decisions by shortstops.

Component 7 Player Games are divided between pitchers and fielders based on the extent to which player winning percentages persist across different sample periods as outlined above. A similar analysis was undertaken to see if the baserunner on first base had any apparent influence on Component 7. Persistence equations were estimated for batters and baserunners. The results were as follows.3. Impact of the Baserunner on First Base on Double Play Ground Balls

Persistence of Component 7 Winning Percentage

Batters: n = 44,744, R^{2}= 0.0347

WinPct_{Even}= (19.84%)•WinPct_{Odd}+ (80.16%)•0.5000 (42.45)

Baserunners: n = 40,584, R^{2}= -0.0167

WinPct_{Even}= (4.21%)•WinPct_{Odd}+ (95.79%)•0.5000 (8.411)

The persistence coefficient is much stronger for batters
(19.8%) than for baserunners
(4.2%). Nevertheless, the persistence coefficient in the baserunner equation is significant with a t-statistic greater than 2. Based on this, I divide offensive credit/blame for Component 7 decisions between batters and baserunners. Batters are given
82.5% of the credit here, which is equal to the batter persistence coefficient,
19.8%, divided by the sum of the two coefficients
(19.8% + 4.2%). Baserunners are credited with the other
17.5% of offensive Component 7 player decisions.

Component 7 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.*

Component 7 leaders can be found here.