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Measuring defense has been one of
the most difficult areas for statisticians to work on and new
or improved statistics are being made available on a regular
basis. The following formulas, descriptions and statistics will
provide you with the common and not-so-common items currently
being used. |
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Defensive Statistics

In Alphabetical
Order |
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Defensive Statistical
Formulas |
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Defensive
Average or [DA]
The Baseball Workshop & Project
Scoresheet has been methodically placing the location of EVERY
hit ball for EVERY game during the last several years. A Defensive
Average, or DA, is the rate at which fielders in their respective
"zone" turn hit balls into an out. The zone, or area
of responsibility, spans the entire field and no section of the
playable field is considered beyond the reach of a fielder. The
Defensive Average statistics is nice because it is analogous
to a fielder's Batting Average Against in that it specifically
measures times reached per opportunity. |
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Fielding Average
(Putouts +
Assists) divided by (Putouts + Assists + Errors)
The fielding average, or fielding
percentage, defensive statistic is the most common rating system
being used in baseball today. It is meant to measure the success
rate of fielding opportunities by each player. The official scorer
for each game plays a role in this statistic by determining if
the hit ball would have required an ordinary amount of effort
to turn the play (thereby charging an error to the fielder if
they did not turn the play) or an extraordinary amount of effort
to turn the play (which does not result in an error charged to
the fielder). The downfall to this statistic is that it almost
rewards fielders who choose not to attempt a difficult play,
thereby avoiding the error, to those that try to turn every hit
ball into a possible out. |
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Fielding Runs
[FR]
Fielding Runs is a common term
for any statistical treatment of fielding that converts a fielder's
performance to runs. Total Baseball uses the most common approach
and most easily understood version. Their approach involves weighting
the number of putouts, assists, and double plays made by each
fielder, and comparing those totals to positional norms of other
fielders to arrive at a figure above or below average. Each extra
out made, or hit allowed, is worth X runs which leads to the
FR figure. Career figures are considered better indicators than
individual seasons as normalization is required for better overall
averaging of each fielder's statistical performance. |
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Range Factor
[RF]
(Putouts +
Assists) x 9 divided by Defensive Innings Played
Range Factor simply stated is
the number of plays MADE per game at the fielding position. It
is better than Fielding Average in several respects: It can be
calculated for almost any player this century and it takes into
account the fielder's own ability to get to a batted ball - rewarding
the more gifted players at each position. Positions can only
be successfully compared to the same position on the field when
using this statistic and early in the season numbers are often
skewed as players chances are not yet normalized. |
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Zone Rating
[ZR]
STATS, Inc. developed their own
defensive rating system to also track locations of EVERY hit
ball for EVERY game played - similar to the above Defensive Average
statistic. The Zone Rating system is different because the area
of responsibility, or zone, for each fielder is considered a
"playable" area and does not account for balls hit
into "Bermuda Triangles", "No Mans Land"
or other impossible to field balls. A fielder that turns a double
play is credited with 2 outs in the ZR system as their play on
the ball actually resulted in both outs versus Defensive Average
which only credits the 1 out. STATS, Inc. books area available
at every bookstore and their work is updated on a yearly basis
for player comparisons. |
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