In this paper, we analyze efforts to encourage teachers' attention to student thinking through a professional development (PD) program. We describe three groups of teachers within the same program who completed different types of assignments, either conducting interviews, planning classroom activities, or both. In both types of assignments, teachers were prompted to explicitly address student thinking. Teachers attended to specifics of student thinking when conducting and analyzing interviews, but struggled to do so when planning activities. While acknowledging the value of sustained attention to revision of lessons, reviewing classroom videos, and utilizing different forms of classroom discourse, we argue that conducting and analyzing interviews is an underused activity that can and should be an important part of teachers' professional development if we seek to encourage attention to student thinking. [For the complete proceedings, see ED583989.]