In the Morris and colleagues example of a system that outputs two wrong words for each input word, word accuracy computed as 1 minus WER is -100 percent.

Checked against its source on October 17, 2026

What it measures: Morris and colleagues use this example to show that WER can exceed 100 percent. Applying the usual accuracy formula to their WER gives a negative value. This is a calculation from their figure, not a number the authors report.
How it is calculated: 1 - 200 percent = 1 - 2.00 = -1.00, which is -100 percent

Calculated from