Definition

The equal error rate (EER) is defined as the point on a receiver operating characteristic (ROC) curve where the false acceptance rate (FAR) equals the false rejection rate (FRR).

center

Operating to the RIGHT of EER (higher FPR, lower TPR):

  • Medical diagnosis where missing a disease is worse than a false alarm
  • Security pre-screening where not detecting a threat is more serious than unnecessary secondary checks

Operating to the LEFT of EER (lower FPR, higher TPR):

  • Legal evidence where false accusations must be minimized
  • Spam filtering where blocking legitimate emails is worse than letting some spam through

source