Schroedinger's Threshold: When the AUC doesn't predict Accuracy
Juri Opitz
The Area Under Curve measure (AUC) seems apt to evaluate and compare diverse
models, possibly without calibration. An important example of AUC application
is the evaluation and benchmarking of models that predict faithfulness of
generated text. But we show that the AUC yields an academic and optimistic
notion of accuracy that can misalign with the actual accuracy observed in
application, yielding significant changes in benchmark rankings. To paint a
more realistic picture of downstream model performance (and prepare a model for
actual application), we explore different calibration modes, testing
calibration data and method.