NASA developed and implemented the NASA Supplemental Classification System (NSCS) in the early 1960's. The purpose of the NSCS was to permit more meaningful recognition of the distinctive aspects of NASA's work - particularly aerospace work-- than the more broadly defined categories of work and occupations defined within the Government-wide position classification system. NASA found that the occupational series used within the Office of Personnel Management's (OPM) system, such as electrical engineering, aerospace engineering, and physics, were much too broad to meet NASA needs and did not recognize the interdisciplinary nature of the work. In addition, the OPM series did not permit the ready identification and tracking of the agency's personnel resources to a degree of specificity desired by NASA management.

Therefore, in order to meet its needs, NASA identified its own work groups and specializations within these groups. Each specialty was assigned a NSCS code number and title, then aligned with an Office of Personnel Management (OPM) series and title. Because the range of work encompassed by an OPM series was often much broader than an NSCS specialty, a single OPM series typically is matched to multiple NASA specialties.