A Student Information System is the operational core of a school's academic records. It manages enrollment, student demographics, class rosters, grades, transcripts, attendance, scheduling, and family contact information. Every other administrative function — billing, admissions, reporting — should be able to draw on the SIS record without re-entering data. In PCR, the SIS is the canonical student record shared by every other module: ERP, CRM, Intelligence, and AI all read and write from the same file.