This meta-analysis offers a snapshot of thirty-five years (1980–2015) of research on instructed second language acquisition (ISLA). Fifty-four empirical studies involving a total of 5,051 second language learners – sampled from six applied linguistics journals, Applied Linguistics, Language Learning, Language Teaching Research, The Modern Language Journal, Studies in Second Language Acquisition, and TESOL Quarterly – were aggregated for the effects of second language (L2) instruction, yielding an overall large effect size, g = 1.06, 95 % CI = 0.84−1.29. Data were further analysed to identify factors that can modulate the efficacy of instruction. While a minor difference was detected between explicit and implicit instruction, statistically significant effects were found for modes of outcome measures, learners’ onset L2 proficiency, research settings, and intensity of instruction.
Primary substance use prevention programs for children and youth: A systematic review
An updated synthesis of research on substance abuse prevention programs can promote enhanced uptake of programs with proven effectiveness, particularly when paired with information relevant to practitioners and policy makers.To assess the strength of the scientific evidence for psychoactive substance abuse prevention programs for school-aged children and youth.A systematic review was conducted of studies published…