The second phase of a 3-year project examining the effect of a process approach to writing instruction on students' expository reading and writing skills, a study determined the impact of three writing programs that emphasized different aspects of a process-oriented writing environment. Data were gathered from 159 fifth and sixth grade students and their teachers. Results indicated that a writing environment emphasizing peer editing and publication and/or instruction in text structure significantly increased students' ability to compose expository text. Findings also showed that writing environment and text structure instruction significantly increased students' ability to summarize information across two expository passages. Data indicated that students in the text structure instruction groups made significant gains in free writing, surpassing the control students on all measures of writing ability. Similar results were obtained both when teachers directed instruction in text structure and when students directed the learning through peer editing and conferences. (Statistical tables are included, and a think sheet for prewriting, student problem/solution text and accompanying worksheet, and compare/contrast pattern guide are appended.) (JD)