Postsecondary education leaders are eager for reliable data to strategically plan for the next year through the next decade, and WICHE's projections of high school graduates are among the most relied upon sources. As WICHE has reported several times since the pandemic began, the disruption to student populations was illustrated with the shift of students previously enrolled in public education to other learning environments. Now, four years later, evidence is amassing that other previously stable factors, such as average annual learning patterns and where families enroll their students, have become less predictable for education, as well as workforce pipeline planning. With this brief, WICHE reviews how the evident K-12 learning impacts might affect projections of high school graduates. Even if enrollments appear to stabilize after pandemic lows, declines in elementary and secondary school learning and proficiency may present additional future challenges for postsecondary education.