While states have made tremendous progress building the capacity to collect longitudinal data, developing the systems and practices to tap into P-20W data remains a nascent effort in most states. This primer aims to provide policymakers with information and recommendations to propel states' progress toward using P-20W data to prepare individuals for today's economy. This primer provides the following information to guide policymakers' efforts: (1) An overview of what it means to link data systems, match data records and share information and why it matters; (2) A snapshot of the data landscape in key sectors with which K-12 needs to share information; (3) Key policymaker actions to support system linkages; and (4) Examples from the field and additional resources to guide state efforts.