This study investigated the principles and practices of a group of three effective ESL writing teachers at UIUC and the impact of their pedagogical decisions on their students' learning. Data collection was done through a period of three weeks and consisted of class observations, class documents and student work examination, teacher surveys, individual and group interviews, and a student survey at the end of their course. Findings from data triangulation showed that these teachers shared many principles on teaching and learning in general and of L2 writing in particular, which align with their classroom practices. In addition, the teachers follow a very similar class structure and have similar approaches to teaching-related activities out of the classroom (such as: lesson preparation before class, creation of their own materials, written feedback and teacher-student conference methods, among others). Nevertheless, despite these similarities, they differed in their idiosyncratic preferences for certain instructional decisions and styles. At the same time, the study findings provide ample evidence of the teaching effectiveness of these teachers which is corroborated by their consistently high university-level teacher evaluation scores, the positive feedback from their specific students on the quality of the course and their teaching, high class scores on the written assignment across classes, positive student self-ratings on their achievement of the course learning outcomes, and additional learning benefits such as greater confidence and the transferability of skills to other areas of academic life
