The Philadelphia Collaborative for Excellence in Teaching Education (CETP) helps develop, implement, and evaluate a new model for science and mathematics K-12 teacher preparation. It involves collaboration of two colleges and a school district. One of the collaborative's main objectives is to redesign the content and pedagogy of core mathematics and science courses so they more effectively emphasize critical instructional strategies. This paper examines whether CETP teaching behaviors are visible in student teachers' actual teaching practices. Student teachers are videotaped at three points during their program. Researchers designed instruments to assess changes in student learning over time. This includes a Demographic and Classroom Observation Survey to provide background information and capture descriptive information about actual lessons and a Student Teacher Videotape Lesson Rating Form to measure whether student teachers exhibit specific behaviors consistent with CETP goals. A Student Teacher Comment form obtains information that cannot not be obtained from videotapes (e.g., lesson goals, lesson planning, and teacher expectations). The Views on Teaching Mathematics and Science Skills form collects student teachers' views on teaching strategies. During students' field experiences, cooperating teachers complete the Cooperating Teachers Evaluation form. The assessment plan was piloted during 1997 and 1998. The major outcome of the pilots was a refinement of the assessment model. During 1998 and 1999, the model will be further piloted and refined. Appendixes contain performance standards and the evaluation forms. (Contains 10 references.) (SM)