Example illustration of the Word Error Rate (WER) analysis, based on the number of deletions, substitutions, and insertions in a transcribed sentence.

An example alignment between the reference annotation (REF) and the actual transcription (ACT), showing deletions (D), substitutions (S), and insertions (I).
(***) are used in the table to denote either a deletion or substitution. For this utterance, there are N = 9 words in the reference annotation [WER = (2 + 1 + 1)/9 = 4/9 or 44.4%].
Example illustration of the Word Error Rate (WER) analysis, based on the number of deletions, substitutions, and insertions in a transcribed sentence.