Providing unbiased data concerning the outcomes of particular intervention methods is imperative if professionals and parents are to assimilate information which could contribute to an "informed choice". An evaluation of Auditory Verbal Therapy (AVT) was conducted using a formal assessment of spoken language as an outcome measure. Spoken language scores were obtained on entry to the study and re-administered at intervals of at least 6 months. Predicted language scores in the absence of Auditory Verbal (AV) intervention were calculated according to a model. Predicted and actual rates of language development (RLD) were compared. The heterogeneity of this group of children derived from their degree of hearing loss, the aetiology of each child"s loss, the type of hearing technology used and the age at which they started therapy. For all age groups and for each of the different hearing technologies, AVT was found to be a highly effective programme for accelerating spoken language development when using RLD as an outcome measure. (Contains 3 tables and 7 figures.)