Content-Rich Interventions on Reading Outcomes in Grades K-3

Abstract

This systematic review examined 17 studies on building knowledge through literacy interventions for students in kindergarten through third grade. Studies were included if they evaluated interventions designed to build knowledge and reported effects on literacy-related outcomes. Most interventions combined explicit vocabulary instruction, thematic text sets, structured discussions, and interactive read-alouds. Positive effects were most common for proximal measures tightly aligned with the taught content, such as science vocabulary or argument writing, while few studies reported gains on standardized measures. Tier 2 interventions—those delivered in small groups—showed somewhat stronger effects on standardized measures than Tier 1 or Tier 3 interventions. Findings highlight that content-rich literacy instruction can meaningfully boost knowledge and vocabulary acquisition, but that these gains may not immediately generalize to standardized reading comprehension. Future research should investigate instructional approaches that foster the flexible application of knowledge and strategies for independent knowledge activation.