A systematic review of language intervention research with low-income families: A word gap prevention perspective

This systematic review sought to document the corpus of language intervention research with low-SES children and help the field move forward. Low-SES children (birth to 8) are at increased risk for infrequent language input from parents (30-Million Word Gap), delays in vocabulary/language, readiness for school, and later school problems. From a repository of 1494 articles published between 1980 and 2016, we identified 513 rigorous intervention reports. We reviewed the 140 studies that included lowSES children in terms of ecological validity, trustworthiness, and readiness for scale-up given a future goal of population-level prevention. Results indicated a relatively high degree of trustworthiness, a moderate degree of ecological validity, and a low degree of readiness for scale-up. All studies used experimental or quasi-experimental designs, the majority being the gold standard, randomized-control trial. Parents and/or other caregivers in authentic settings were the intended intervention implementers (ecological validity). However, research staff implemented the majority of interventions. Most studies were early-to mid-stage, none directly investigated scale-up. Weaknesses in scale-up readiness were infrastructure (i.e., manuals), community engagement (i.e., social validity), and progress monitoring/evaluation (i.e., technology), among others (i.e., cost). We identified 37 areas of improvement in future research with implications for preventing the Word Gap. (C) 2019 Elsevier Inc. All rights reserved.