In a study of 40 adults with sensorineural hearing loss, Guthrie and Mackersie found that for people with moderately severe or severe losses, presenting words 5 dB below their uncomfortable loudness level gave the highest phoneme recognition scores.

Checked against its source on October 17, 2026

In the source's own words

“For participants with moderately severe/severe losses, the UCL - 5 dB method resulted in the highest phoneme recognition scores”

A Comparison of Presentation Levels to Maximize Word Recognition Scores, Leslie A. Guthrie and Carol L. Mackersie, Journal of the American Academy of Audiology, 2009, Abstract (Results).

What it measures: Performance-intensity functions were measured for 40 participants with sensorineural hearing loss, with word levels from 10 dB above the speech recognition threshold to 5 dB below the uncomfortable loudness level. The study used the Computer-Assisted Speech Perception Assessment.
What it does not show: The sample was 40 adults with sensorineural loss, so the result may not carry over to children, to other types of hearing loss or to other word lists. Some other groups did best at other levels.