The WRITE (Writing Research to Improve Teaching and Evaluation) Center for Secondary Students researches academic writing in middle and high school. We are extending best practices learned in the English language arts classrooms from three nationally recognized interventions into history classes. The WRITE Center is excited to provide middle and high school history teachers with the tools and strategies to improve their students' source-based argument writing, a critical component not only of Common Core State Standards, but academic and professional writing. We partner with teachers and administrators to create relevant and practical professional development opportunities. In addition, we are using quantitative and qualitative research methods, including data mining techniques and automated natural language processing, to look at existing source-based writing samples from ELA classes to understand the development of good writers longitudinally, which will then be compared to writing in history classes to understand the similarities and differences between the two contexts.