For 25 years, the National Institute for Excellence in Teaching (NIET) has partnered with states, districts, schools, and educator preparation programs to strengthen educator effectiveness and improve student achievement. This research summary provides an opportunity to reflect on the impact of NIET's initiatives on educator effectiveness, student achievement, and leadership development. Drawing on studies conducted by NIET from the past five years, this report highlights how NIET's TAP System for Teacher and Student Advancement (TAP System), teacher and leader development, and educator preparation partnerships enhance instructional quality, strengthen workforce stability, and support student success. Key findings include: (1) schools implementing the TAP System have seen improvements in teacher effectiveness, retention, and student achievement; (2) NIET's recommended practices increase both satisfaction with and application of professional development; (3) NIET's training and support strengthen instructional leadership, raise school leader self-efficacy, and drive positive change in rural and high-need districts; and (4) NIET's partnerships with educator preparation programs help bridge coursework and clinical practice, ensuring aspiring teachers and school leaders are trained to meet the instructional expectations of real classrooms, resulting in better-prepared educators.