Barry Larkin's 1991 Double Play Efficiency

Tuesday, February 01 2005 @ 08:54 AM EST

Contributed by: Mike Green

This article, the second in a series, results from the joint efforts of Jonny German and Mike Green. It began with Mike's Hall watch series on shortstops and the search for more reliable objective measures of Barry Larkin's defence than were otherwise available. In the first piece, we attempted to evaluate Barry Larkin's efficiency in converting ground balls into outs. This time, we attempt the same thing for the double play ball, again using a play-by-play analysis.

We begin with a restatement of the basic information from Part 1 of the series.

The event file and hit diagram

The Retrosheet event file for Cincinnati's 1991 season contains a pitch by pitch and play by play account of every game of the season. Players, umpires, weather conditions and even noteworthy radio calls of unusual plays are recorded. It is a fabulous resource. Most importantly for us, it contains the location of every batted ball, using the Project Scoresheet Hit location diagram. The infield portion of the diagram is reproduced below; the full diagram can be seen here.

The events file records a play using the notation:"standard numerical account/hit location"
To understand the way it works, here are a couple of examples. If a hitter grounds out on a ball hit directly at the shortstop, the events file will record "63/G6". The first half "63" means that it is an ordinary 6-3 play, fielded by the shortstop who throws on to first for the putout. The second half "G6" means that it is a ground ball fielded in the "6" zone in the diagram above.

If the hitter grounds out to the shortstop on a ball up the middle on the shortstop side of the bag, the events file will record "63/G6M". If the hitter grounds out to the shortstop on a ball in the hole, the events file will record "63/G56". A ground single through the hole will be recorded as "S7/G56D".

The method and results

To evaluate Barry Larkin's double play efficiency, we counted ground balls in the various zones for the shortstop, second baseman, first baseman and pitcher with a runner on first and less than two out for Larkin, other Cincinnati shortstops and the opposition, and the number of such balls that were converted into double plays. We then calculated the number of total double plays that Larkin was involved in compared with the number that could be expected (using his opportunities and the opposition's conversion rate). Finally, we attempt to apportion credit or blame for the results among Larkin and the other Cincinnati infielders.

             Larkin    Other Cin. SS     Opposn. SS      Larkin's efficiency


5-6 hole
Conversions   0             0                  1
Opportunities 19 5 23
Conv. rate 0% 0% 4.3%

Larkin's performance  4.3% X 19 opps=1 expected (0 actual)=    -1

at him
Conversions   13            6                  14
Opportunities 26 9 35
Conv. rate 50% 66.7% 40%

Larkin's performance  40% X 26 opps= 10 expected (13 actual)=   3

up the middle
Conversions   12            6                  15
Opportunities 26 13 30
Conv. rate 46.2% 46.2% 50%

Larkin's performance  50% x 26 opps= 13 expected (12 actual)=  -1


at him
Conversions   14            5                  11
Opportunities 31 9 33
Conv. rate 45.2% 55.6% 33.3%

Larkin's performance  33.3% X 31 opps= 10 expected (14 actual)= 3

up the middle
Conversions   6             3                  7
Opportunities 10 12 20
Conv. rate 60.0% 25.0% 35%

Larkin's performance  35% x 10 opps= 4 expected (6 actual)=     2

total expected vs. actual 6-4-3 and 4-6-3                 =     6

3-6-3 or 3-6-1

3-4 hole
Conversions   4             1                  0
Opportunities 24 6 19
Conv. rate 16.7% 16.7% 0%

at him
Conversions   1             0                  4
Opportunities 6 1 11
Conv. rate 16.6% 0% 36.4%
Total rate 16.6% 14.3 13.3%

Larkin's performance  13.3% X 30 opps= 4 expected (5 actual)=   1


at him
Conversions   2             0                  2
Opportunities 12 1 14
Conv. rate 16.7% 0% 14.3%

Larkin's performance  14.3% X 12 opps= 2 expected (2 actual)=   0

Our interpretation

The Cincinnati Reds turned 6 more total 4-6-3 and 6-4-3 double plays than expected bearing in mind the number of opportunities and the opposition success rate when Larkin was in the game. We attribute 1/2 of that success to Larkin and 1/2 to the second baseman, so we credit Barry Larkin with 3 additional assists over the season.

For the 3-6-3 and 3-6-1 play, we grouped all the data. It seems likely that the conversion rate on average should be fairly similar whether the first baseman fields the ball at the bag or moving towards second base. The overall conversion rates were similar, although Cincinnati did much better in one, and the opposition in another. We attribute this to the small size of the sample. Cincinnati turned 1 more double play begun by the first baseman than would be expected. In light of the fact that the throw from first base is particularly difficult, it seems most reasonable to credit this surplus to the first baseman.

For the 1-6-3, Cincinnati performed exactly as expected.

To sum up, we credit Barry Larkin with 3 additional assists worth 2 runs in his 119 games in 1991 by virtue of his double play efficiency.

Comparison with alternative method

We have credited Barry Larkin with 3 additional assists on double plays, and in our first segment, we credited him with 12 additional assists on ground balls, for a total of 15 additional assists. He played 119 games. As we pointed out in the first segment, he had 28 more assists than the average shortstop on a pro-rated basis. Is there an explanation? We noted that Larkin had many more ground ball opportunities on balls up the middle. In fact, there were 30 more such opportunities than the opposition on a pro-rated basis. He did have 9 fewer opportunities in the hole and 8 fewer opportunities at him. Similarly, Larkin had significantly more double play opportunities on a pro-rated basis than the opposition, most notably on the 4-6-3. He had as many opportunities in this situation in 119 games than the opposition did over the season. Overall, it appears that Larkin did have significantly more opportunities to make plays, and this accounts for the bulk of the difference in the two methods. It does seem likely that the assists/inning approach does result in an overestimate of Larkin's efficiency.

In our 3rd installment, we'll look at balls in the air, pop-ups, line drives, short fly balls and bloopers.

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