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## Speed Scores and Reaching Base on Errors

by Dan Levitt

In a previous essay I examined the effect of team speed on opposition errors.  This essay expands the analysis by looking at individual players

I examined the effect of speed on reaching base on error by looking at all 219 batters who had at least 300 at bats in 1980 using the 1980 Retrosheet files.  As a proxy for player speed I used the Bill James Speed Score.  The table below summarizes the data by breaking it into quintiles.  I also looked at correlations based on the 219 individual player records.

Quint   SpdScr  RBoE    Opp     /Opp    RBoE.GB Opp.GB  /Opp.GB
1       3.67    259     11498   .0225   252     5751    .0438
2       4.84    277     11370   .0244   264     5620    .0470
3       5.49    276     11943   .0231   267     6073    .0440
4       6.82    300     12559   .0239   289     6519    .0443
5       10.95   370     13690   .0270   359     7596    .0473

Quint:    Speed Score Quintile
SpdScr:   Top Bill James Speed Score of the Quintile
RBoE:     Reached base on error
Opp:      Opportunities--At bats that put the ball in play but did not result in a hit.
/Opp:     RBoE per opportunity
RBoE.GB:  Reached base on error on ground ball
Opp.GB:   Opportunities on ground balls only
/Opp.GB:  RBoE.GB per GB opportunity

Summary:  A very modest correlation of .14 exists between reaching base on error per opportunity and a player's speed score.  Because nearly all times first base is reached on error comes on a ground ball, much of this correlation can be explained by the relationship between speed scores and the propensity to hit ground balls (correlation = .30), i.e. faster players tend to be ground ball hitters.  When one looks at times reached base on error as a percentage of non-basehit ground balls the correlation between speed and reaching base on error evaporates to basically zero (correlation = .04).

As a further inquiry I examined whether reaching base by error is related to whether a hitter bats left-handed or right-handed.

Quint   Bats    RBoE    Opp     /Opp    RBoE.GB Opp.GB  /Opp.GB
4       L       133     6143    .0217   129     3113    .0414

R       167     6416    .0260   160     3406    .0470
5       L       156     6139    .0254   152     3571    .0426

R       214     7551    .0283   207     4025    .0514
All     L       538     25291   .0213   522     13501   .0387

R       944     35769   .0264   909     18058   .0503

Bats:  The side of the plate the at bat took place from.  Switch hitter at bats are therefore split. All other columns are the same as above.

Summary: Here it seems fairly conclusive that those hitting from the right side are much more likely to reach base on error than those hitting from the left side.  I would suppose righties are more likely to reach base on error because they are more likely to hit to the SS or 3B who typically make more errors (mainly due to the longer throw) than first or second basemen.

Appendix:  A note on Speed Scores

Bill James developed Speed Scores as a method for determining a player's practical game condition speed.  It is calculated by averaging the top five of six different statistics.  The scale for players ranges from approximately one for the slowest players to ten for the fastest.  In my analysis, for simplicity, I use only five of the statistics (the one not used is Range Factor).

 SpS1 Speed score based on SB% ((SB+3)/(SB+CS+7)-0.4)*20 SpS2 Speed score based on SB attempts SQRT((SB+CS)/((H-2B-3B-HR)+BB+HP))/0.07 SpS3 Speed score based on triples 3B/(AB-HR-K)/0.02*10 SpS4 Speed score based on runs per time on base ((R-HR)/(H+BB-HR-HP)-0.1)/0.04 SpS5 Speed score based on GDP's (0.055-GDP/(AB-HR-K))/0.005 Speed Score Net Speed Score Average of top 4 Speed Scores above

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