trimTrees (version 1.2)

hitRate: Empirical Hit Rates for a Crowd of Forecasters

Description

This function calculates the empirical hit rates for a crowd of forecasters over a testing set. The function takes as its arguments the forecasters' probability integral transform (PIT) values -- one for each testing set row -- and the prediction interval of interest.

Usage

hitRate(matrixPIT, interval = c(0.25, 0.75))

Arguments

matrixPIT

A ntest-by-nForecaster matrix of PIT values where ntest is the number of rows in the testing set and nForecaster is the number of forecasters. Each column represents a different forecaster's PITs for the testing set. A PIT value is the forecaster's cdf evaluated at the realization of the response in the testing set.

interval

Prediction interval of interest. The default interval=c(0.25, 0.75) is the central 50% prediction interval.

Value

HR

An nForecaster vector of empirical hit rates -- one for each forecaster. A forecaster's empirical hit rate is the percentage of PIT values that fall within [interval[1],interval[2]], e.g., [0.25,0.75] according to the default.

References

Grushka-Cockayne Y, Jose VRR, Lichtendahl KC Jr. (2014). Ensembles of overfit and overconfident forecasts, working paper.

See Also

trimTrees, cinbag

Examples

# Load the data
set.seed(201) # Can be removed; useful for replication
data <- as.data.frame(mlbench.friedman1(500, sd=1))
summary(data)

# Prepare data for trimming
train <- data[1:400, ]
test <- data[401:500, ]
xtrain <- train[,-11]  
ytrain <- train[,11]
xtest <- test[,-11]
ytest <- test[,11]
      
# Run trimTrees
set.seed(201) # Can be removed; useful for replication
tt <- trimTrees(xtrain, ytrain, xtest, ytest, trim=0.15)

# Outputs from trimTrees
mean(hitRate(tt$treePITs))
hitRate(tt$trimmedEnsemblePITs)
hitRate(tt$untrimmedEnsemblePITs)