This document summarizes a research paper that reviewed studies on writing programs for grades 2-12. It identified 14 studies of 12 programs that met rigorous research standards. The programs fell into three categories: writing process models, cooperative learning models, and models focusing on reading-writing interactions. Writing process models, like Self-Regulated Strategy Development, had a positive average effect on writing achievement (ES=+0.17). Cooperative learning models and reading-writing interaction models also saw positive average effects (ES=+0.16 and ES=+0.19 respectively). Overall, programs in all three categories improved writing outcomes on average based on studies meeting high research standards.