Fact · Speech recognition
43percent word error rate
In a 1997 review, an HMM recognizer had a word error rate of 43 percent on the spontaneous telephone conversations of the Switchboard corpus.
Checked against its source on October 17, 2026
In the source's own words
“The 43% error rate of the HMM recognizer is extremely high compared to the much lower machine rates”
Speech recognition by machines and humans, Richard P. Lippmann, Speech Communication, vol. 22, pp. 1-15, 1997, Section 4.4 (Switchboard).
Open the original- What it measures
- The recognizer was a high-performance HMM system of the mid-1990s, described in a 1996 paper the review cites. Switchboard is spontaneous speech between strangers on the telephone.
- What it does not show
- A 1990s system on one corpus. Later systems did far better on the same kind of speech (see the 2016 Microsoft result).