Data from the National Assessment of Educational Progress and accompanying machine-readable documentation are currently maintained on the National Military Command Information Processing System (NIPS) data base management system. National Assessment's data management and file processing systems, however, are not well-suited to secondary users. Because substantial resources and external assistance would be required to document the National Assessment data files more clearly and make them easy to use, the Education Commission of the States (ECS) participated in a National Science Foundation grant to study the utility of secondary analysis with National Assessment data. The design phase, compromise and rejected alternatives, implementation, contents of the public use data tapes, and utilization are described. Currently, National Assessment staff are involved in three tape-related activities: enhancing the existing tapes, creating new tapes, and developing an introduction to the public-use data tapes. (Author/GK)