| EnsRoca {easyVerification} | R Documentation |
Computes the area under the ROC curve given the observations.
EnsRoca computes the Area Under the Curve (AUC). For ease of interpretation,
EnsRocss converts the AUC to the range from -1 to 1 with zero indicating
a forecast with no discrimination.
EnsRoca(ens, obs, use.easy = FALSE) EnsRocss(ens, obs, use.easy = FALSE)
ens |
n x j matrix of n probability forecasts for j categories |
obs |
n x j matrix of occurence of n verifying observations in j categories |
use.easy |
logical, should implementation of standard errors as implemented
in |
If used with SpecsVerification >= 0.5, the standard errors as implemented
in the function SpecsVerification::Auc are used.
If use.easy = TRUE or when used with an older version of SpecsVerification,
the standard error σ of the ROC area
skill score is given by the following formula after Broecker (2012).
σ^2 = 1/3 (1/N0 + 1/N1 + 1/(N0 N1))
Where σ is the standard error, N1 the number of
events, and N0 the number of non-events in category i.
Broecker, J. (2012). Probability forecasts. Forecast Verification: A Practitioner's Guide in Atmospheric Science, Second Edition, 119-139.
tm <- toymodel()
## compute ROC area for tercile forecasts using veriApply
veriApply("EnsRoca", fcst=tm$fcst, obs=tm$obs, prob=1:2/3)