The Efficacy of Recasts in Language Intervention (Cleave et al., 2015)

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.

研究目的：本系统综述（systematic review）与元分析（meta-analysis）旨在批判性评估会话重铸（conversational recasts）对语言障碍儿童语法发展的有效性相关研究证据。
研究方法：本研究开展两项互补且各具特色的综述工作，并将其整合分析。通过系统文献检索，共纳入35篇文献用于系统综述。所纳入研究涵盖多种研究设计类型，但所有研究均以重铸为核心干预要素。元分析仅纳入可计算效应量（effect sizes）的研究，同时纳入将重铸作为主要干预部分的组合干预方案。最终纳入14项研究，其中7项同时被系统综述收录。研究按研究阶段分组，并进行质量评级。
研究结果：研究质量及证据强度存在显著差异。尽管如此，在所有研究阶段中，绝大多数研究均支持重铸干预的应用价值。元分析结果显示，近端测量指标的平均效应量为0.96，远端测量指标的平均效应量为0.76，对应约0.75至1.00个标准差的正向获益。
研究结论：现有研究证据存在一定局限性，但仍支持将重铸应用于语法干预当中。本文同时讨论了语法干预中重铸的关键特征。