Dave Van Riper is a geographer with a deep interest in facilitating access to large volumes of data published by statistical agencies in the United States and throughout the world. As co–principal investigator of IPUMS National Historic Geographic Information System (NHGIS) and director of spatial analysis at IPUMS, the preeminent source of harmonized census and survey data, Van Riper designs data access systems that help students, researchers, and policy analysts easily obtain data they need.