The efficacy of recasts in language intervention: a systematic review and meta-analysis.

PURPOSE: This systematic review and meta-analysis critically evaluated the research evidence on the effectiveness of conversational recasts in grammatical development for children with language impairments. METHOD: Two different but complementary reviews were conducted and then integrated. Systematic searches of the literature resulted in 35 articles for the systematic review. Studies that employed a wide variety of study designs were involved, but all examined interventions where recasts were the key component. The meta-analysis only included studies that allowed the calculation of effect sizes, but it did include package interventions in which recasts were a major part. Fourteen studies were included, 7 of which were also in the systematic review. Studies were grouped according to research phase and were rated for quality. RESULTS: Study quality and thus strength of evidence varied substantially. Nevertheless, across all phases, the vast majority of studies provided support for the use of recasts. Meta-analyses found average effect sizes of .96 for proximal measures and .76 for distal measures, reflecting a positive benefit of about 0.75 to 1.00 standard deviation. CONCLUSION: The available evidence is limited, but it is supportive of the use of recasts in grammatical intervention. Critical features of recasts in grammatical interventions are discussed.

Grammatical outcomes of 3- and 6-year-old children who are hard of hearing.

PURPOSE: Spoken language skills of 3- and 6-year-old children who are hard of hearing (HH) were compared with those of children with normal hearing (NH). METHOD: Language skills were measured via mean length of utterance in words (MLUw) and percent correct use of finite verb morphology in obligatory contexts based on spontaneous conversational samples gathered from 185 children (145 HH, 40 NH). Aided speech intelligibility index (SII), better-ear pure-tone average (BE-PTA), maternal education, and age of amplification were used to predict outcomes within the HH group. RESULTS: On average, the HH group had MLUws that were 0.25-0.5 words shorter than the NH group at both ages, and they produced fewer obligatory verb morphemes. After age, aided SII and age of amplification predicted MLUw. Aided SII and BE-PTA were not interchangeable in this analysis. Age followed by either BE-PTA or aided SII best predicted verb morphology use. CONCLUSIONS: Children who are HH lag behind their peers with NH in grammatical aspects of language. Although some children appear to catch up, more than half of the children who are HH fell below the 25th percentile. Continued monitoring of language outcomes is warranted considering that children who are HH are at increased risk for language learning difficulties.