prediction-class: Class "prediction"
Description
Object to encapsulate numerical predictions together with the
  corresponding true class labels, optionally collecting predictions and
  labels for several cross-validation or bootstrapping runs.Objects from the Class
Objects can be created by using the
  prediction function.References
A detailed list of references can be found on the ROCR
  homepage at http://rocr.bioinf.mpi-sb.mpg.de.