There is one research-grounded treatment that has a strong impact on improving how well students write, especially struggling writers. This involves explicitly teaching students how to plan, revise, and edit their papers (teachers model how to use strategies and provide students with guided practice aimed at promoting effective and independent use). In 20 experimental studies reviewed by Graham and Perin (2007), such instruction improved the quality of students' writing in every single investigation. Particularly effective was a specific model for teaching writing strategies. The Self-Regulated Strategy Development model (see Harris, Graham, & Mason, 2006) not only involves modeling and guided practice, students are also taught the knowledge and skills needed to apply the strategies as well as procedures for regulating their use. Furthermore, this instruction is criterion-instead of time-based. This means that instruction continues for youngsters until they reach mastery, instead of providing a set number of instructional sessions.