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Problems with Gerrity Scores greater 1


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Hello

For a statistical experiment I am calculating lots of Gerrity Skill Scores for contingency tables derived from Temperature forecasts/observations.

I tried the package for R, and when I use some relative probabilities as baseline that I have derived from climatological data, I sometimes get Scores greater than 1. I am pretty sure this should not happen.

Here is a script that can be run in batch mode R which should reproduce the error:

 

library('verification')
A=matrix(c(2394,481,0,0,0,0,4718,1399,0,0,0,0,1740,1755,0,0,0,0,3202,594,0,0,0,0,1717),nrow=5)
pb=c(0.0632,0.2692,0.1461,0.2338,0.2877)
multi.cont(A,pb)

 

 

I know that the contingency table does not represent the baseline probabilities, but I am still puzzled that this happens.

I also coded the procedure in matlab myself, with the information from the original paper and it reproduces the error.

Is there a condition about the baseline probabilities that I am not aware of?

Any Help is welcome.

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Hello

For a statistical experiment I am calculating lots of Gerrity Skill Scores for contingency tables derived from Temperature forecasts/observations.

I tried the package for R, and when I use some relative probabilities as baseline that I have derived from climatological data, I sometimes get Scores greater than 1. I am pretty sure this should not happen.

Here is a script that can be run in batch mode R which should reproduce the error:

 

library('verification')

A=matrix(c(2394,481,0,0,0,0,4718,1399,0,0,0,0,1740,1755,0,0,0,0,3202,594,0,0,0,0,1717),nrow=5)

pb=c(0.0632,0.2692,0.1461,0.2338,0.2877)

multi.cont(A,pb)

 

 

I know that the contingency table does not represent the baseline probabilities, but I am still puzzled that this happens.

I also coded the procedure in matlab myself, with the information from the original paper and it reproduces the error.

Is there a condition about the baseline probabilities that I am not aware of?

Any Help is welcome.

I work in matlab, send me that code if you want and I can look. 

Winter 23-24: Total Snow (3.2")    Total Ice (0.2")     Coldest Low: 1F     Coldest High: 5F

Snow Events: 0.1" Jan 5th, 0.2" Jan 9th, 1.6" Jan 14, 0.2" (ice) Jan 22, 1.3" Feb 12

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