Word Error Rate

A metric used to evaluate the accuracy of automatic speech recognition (ASR) and captioning systems, calculated as the number of word-level errors (insertions, deletions, and substitutions) divided by the total number of words in the reference transcript. Lower WER indicates higher transcription accuracy. For deaf and hard of hearing users who rely on captions, WER directly affects comprehension—research suggests WER above 10% significantly degrades understanding, while professional CART services typically achieve WER below 2%.