Creating Geographic Rating Area Maps: How to Combine Counties, Split Counties, and use Zip Code Boundaries

SAS/GRAPH® will be used to create choropleth maps that identify the geographic rating areas implemented by the Affordable Care Act (ACA). The default areas for each state are Metropolitan Statistical Areas (MSAs) plus the remainder of the State that is not included in a MSA. States may seek approval to base the rating areas on counties or three-digit zip codes, which requires that counties be combined in some states and split in two in others. For the states that use zip codes to identify the rating areas, ZIP code tabulation area (ZCTA) files are used, which are derived from an ESRI® shapefile format (.shp) and are obtained from the U.S. Census Bureau. Also demonstrated will be the utilization of the annotate facility to identify each area and place major cities on the maps.