This narrative case study describes the use of improvement science methods to strengthen the effectiveness of field experiences for teacher candidates. As part of a networked improvement community, we sought to reduce variation in the quality of field experience by providing a cohesive network of high-quality coaching supports. Using design-based methods grounded in the principles of improvement, we analyzed seven learning, design, and testing rounds to reduce variation in teacher candidates' experiences as student teachers or interns. Results from early learning rounds suggested considerable structural variability in how supervisors conducted their POP cycles. The structural variability from these rounds led to two key change ideas to address variation in teacher candidates field experiences: a common POP cycle protocol and the use of a POP-cycle-aligned reflection form. The principles and tools of improvement highlighted small but significant changes to how supervisors support teachers within their field experiences.