Reliability of audiologists' ratings of the intelligibility of hearing-impaired children's speech.

The reliability of intelligibility judgments of hearing-impaired children's speech was investigated. Twenty Australian audiologists, untrained in the use of speech intelligibility scales, rated the speech intelligibility of 20 hearing-impaired children, using the National Technical Institute for the Deaf speech intelligibility scale on one occasion and a percentage intelligible scale on another. Inter-rater reliability was high for both scales (Kendall's W greater than 0.80, p less than 0.001), as was intra-rater reliability (r greater than 0.90, p less than 0.001; rcc greater than 0.88). Training in the use of speech intelligibility rating procedures does not appear necessary for reliable judgments. However, the perceived intelligibility of some children's speech was highly listener dependent regardless of the scale used, indicating that a variance measure should be reported in addition to means in descriptions of perceived intelligibility.