Despite evidence that tiered instruction within response to intervention (RTI) frameworks is important for students with reading difficulties, no complementary professional development (PD) research demonstrates how teachers can develop knowledge necessary to implement coordinated evidence-based instruction across instructional tiers. One promising PD approach combines lesson study (LS) with content-focused PD sessions; PD sessions introduce teachers to new knowledge, while LS supports teachers in integrating knowledge into their instructional repertoires. We used grounded theory methods to investigate how teams of upper elementary teachers’ ( n = 7) understandings of coordinated, tiered reading instruction changed through participation in Project InSync, a year-long PD consisting of content-focused PD workshops and LS cycles. Results indicate that, through interactions during LS sessions, teachers developed more sophisticated and integrated understandings of word study content, pedagogical practices, students’ struggles with literacy, and coordinating instruction across instructional tiers. Results have implications for teacher PD within RTI frameworks.
