tgetcal: Get a linear or quadratic calibration of ternary forecast / observation data

Description

Function to obtain a best-fitting calibration to a set of ternary forecasts p and corresponding observations o.

Usage

tgetcal(tv, quad = FALSE)

Arguments

tv: An object of the tverify class (as produced by tverify).
quad: A logical describing which functional form to use for calibration. Linear calibration (quad = FALSE) is faster. Quadratic calibration (quad = TRUE) is more sophisticated but can be slow for large data sets.

Author

Tim Jupp

References

Jupp TE, Lowe R, Stephenson DB, Coelho CAS (2012) On the visualization, verification and recalibration of ternary probabilistic forecasts, Philosophical Transactions of the Royal Society, volume 370, pages 1100-1120.

https://rsta.royalsocietypublishing.org/content/370/1962/1100.full/

https://arxiv.org/abs/1103.1303/

Examples

Run this code

data(foot)
# see the distribution of forecasts
tplot(foot$p,main="Bookmaker forecasts of \n football matches",
      dimnames=c("Home Win","Draw","Away Win"))
      
# see how well forecasts compare with results
# create object of class tverify
foot.verify <- tverify(p=foot$p,o=foot$o) 

# plot ternary reliability diagram
dev.new()
plot(foot.verify, thresh=3)    
           
# get a (linear) calibration of these data
# create an object of class tverify
foot.calib <- tgetcal(foot.verify) 

# plot ternary reliability diagram of calibrated forecasts       
dev.new()
plot(foot.calib, thresh=3)