A study focused on a university-school collaborative research project on language assessment in the classroom context and the benefits of preservice teacher participation. Personnel from the Pennsylvania State University (including 20 preservice teacher education students), intermediate unit (Pennsylvania's regional service centers), and four classroom teachers developed a cooperation that led to changes in assessment, especially regarding portfolio implementation. A preservice participant became an integral part of the project; she performed theoretical research and recorded meetings and conferences. However, her involvement grew to include classroom visitations allowing her to develop working relationships with classroom teachers who were, in essence, classroom researchers. Once she became a classroom teacher, she realized the experiences of the project naturally became a part of her personal instructional and researching practices. The project was a success as a collaborative effort and the collaboration enabled the participants to coordinate a sustainable approach to assessment in classrooms working in or towards a holistic approach to language instruction. (Contains 17 references.) (RS)