Terms: medical service study area – mssa
Medical Service Study Areas (MSSA) are the defined geographic analysis unit for the Office of Statewide Health Planning and Development (OSHPD) and are reproduced on the decadal census. The boundaries are approved by the Health Manpower Policy Commission and the U.S. Department of Health and Human Services, Health Resources Service and Administration (HRSA) formally recognizes California MSSAs as the Rational Service Area (RSA) for medical service for California. They are composed of one or more complete U.S. Census Bureau census tracts.
Source and for further information: California Health Workforce Catalog http://gis.ca.gov/catalog/BrowseRecord.epl?id=23784