This memo, which is the fourth in the series, describes how 11 Virginia school divisions have come together to form Virginia's Student-Led Assessment Networked Improvement Community. This Networked Improvement Community (NIC) is focused on increasing the use of student-led assessment practices, including capstone projects, to increase students' agency and ownership of their learning and assessment experiences. The work of this NIC is supported by local- and state-level efforts to reimagine assessment in ways that shift the balance from a heavy focus on standardized assessments to one that prioritizes student-centered learning. The NIC's use of improvement science practices encouraged shared goal setting, progress monitoring, and iterative cycles that supported learning and refinement of the group's ideas for improving student-centered learning. This collective effort to reimagine assessment fostered sustained improvements in the midst of leadership churn. [To read the third memo in the series, "Developing a School Culture of Meaningful Feedback Deepens Everyone's Learning," see ED600643.]