The Dutch Inspectorate for Education established that the quality of elementary students’ writing is below the desired level, and that the teaching of writing must be improved. The aim of this PhD research was therefore to improve writing education in upper elementary grades by developing an effective teaching program for writing, including professional development for teachers, and tools for the assessment of writing. Building on the findings of previous research, we developed and tested Tekster [Texter], a strategy-focused comprehensive program for teaching writing in grade 4 to 6. Tekster combines several evidence-based practices, such as strategy instruction, goal setting, text structure instruction and observational learning into one g...