What stats I know I taught myself.....so I don't know if the following is
legit.
If I want to compare a player from the 70s to a player from the 80s will the
following work.
Calculate league average RC/27 for the year(s) in question
Calculate each players RC/27
Calculate the % difference in the league average RC/27 between the years
Apply that % to the players RC/27
is this accurate?
Or do you have to do the league average on a lower level, for example
calculate the % difference in H, BB, 2B, 3B, HR...etc...then apply that to
the players raw numbers and then do the RC/27 calculation.
next...if I have old data from a year....all the player data. Can someone
explain to me how to calculate stadium adjustments? And can they be applied
like the year adjustments above?
thanks for the stats lesson
mike
>If I want to compare a player from the 70s to a player from the 80s will the
>following work.
>
>Calculate league average RC/27 for the year(s) in question
>Calculate each players RC/27
>Calculate the % difference in the league average RC/27 between the years
>Apply that % to the players RC/27
>
> is this accurate?
Seems okay to me. The usual method is to compare the player to the
league average, but your method should give the same results.
>Or do you have to do the league average on a lower level, for example
>calculate the % difference in H, BB, 2B, 3B, HR...etc...then apply that to
>the players raw numbers and then do the RC/27 calculation.
Not necessary. Doing the adjustments on the RC/27 data is perfectly
fine.
>next...if I have old data from a year....all the player data. Can someone
>explain to me how to calculate stadium adjustments? And can they be applied
>like the year adjustments above?
Roughly, calculate the difference between the runs per inning for both
teams in each team's home and road game; use that ratio to adjust the
player stats. Using Total Baseball's figures is easier than
calcuating it yourself.
------------
Clifford Blau
http://users.erols.com/brak
> What stats I know I taught myself.....so I don't know if the following is
> legit.
>
> If I want to compare a player from the 70s to a player from the 80s will the
> following work.
>
> Calculate league average RC/27 for the year(s) in question
> Calculate each players RC/27
> Calculate the % difference in the league average RC/27 between the years
> Apply that % to the players RC/27
>
> is this accurate?
This is the correct method. RC/27 is a measure of value, and you want
to estimate a player's value in a different context. An average player
in 1975 and an average player in 1985 did just as much to help their
teams win.
> Or do you have to do the league average on a lower level, for example
> calculate the % difference in H, BB, 2B, 3B, HR...etc...then apply that to
> the players raw numbers and then do the RC/27 calculation.
You might want to do this if you wanted to estimate how a player woul
ddo under different condition.
> next...if I have old data from a year....all the player data. Can someone
> explain to me how to calculate stadium adjustments? And can they be applied
> like the year adjustments above?
To compute a park effect, let P be the ratio between runs scored in the
park and runs scored in the team's road games (thus by the same
players), and N the number of teams in the league. The park factor is
N(1+P)/(2N-2+2P); it is slightly less than half as strong as the park
effect because you are comparing a team playing half its games in the
park to a league playing 1/N of its games in the park. For example, if
there are 640 runs scored in Dodger Stadium and 800 in Dodgers road
games in a 16-team league, the park factor is 16(1.8)/(32-2+1.6)=0.911.
To use a park factor, divide any run-dominated figure by the park
factor. Thus, in the above example, a 3.64 ERA in Dodger Stadium
corresponds to 4.0 in a neutral park, and 91 RC in Dodger Stadium
corresponder to 100 in a neutral park. To adjust OBP or SLG, use the
square root of the park factor; if a team's OBP and SLG are both
mutliplied by X, then its OBP*SLG, which is proportional to runs, will
be mutliplied by X^2.