The effectiveness of horizontal evaluation for student teachers and their supervisors was explored through a qualitative analysis of three case studies. For the case studies, two of the supervising teachers were university-based, while the third was a secondary school teacher with no prior experience in supervising student teachers. The aim of the horizontal evaluation model was to expand the scope of evaluation so that supervision focused on linking educational theories and objectives to practice. The stated short term and long term goals of the student teachers were the basis for evaluation. Supervisors observed the student teachers for one lesson and discussed their observations with them in a conference. The supervisors were then trained in the use of horizontal evaluation and used the model to observe and critique four subsequent lessons for each of the student teachers. These lessons and the resulting supervisory conferences were videotaped to facilitate analysis both for the conferences and for the qualitative analysis of the case studies. Five themes emerged from application of the model. The analysis of the link between teachers' intents and practice received increased emphasis. There was a shift toward critically assessing instructional practice. A tendency to analyze practice in terms of holistic themes emerged. The valuative nature of teaching received increased attention. There was a movement away from supervisor-dominated agenda setting toward a greater balance between student teacher and supervisor initiation of discussion topics. (Authors/FG)