A New Tool for the Spatial Aggregation of Health Data

In public health surveillance, aggregation may be necessary to preserve the confidentiality of those diagnosed with illnesses or to show stable rates in areas with sparse population. To accomplish this a user friendly application was developed to group smaller neighboring geographic areas into larger regions using SAS version 9.2. The two step process first creates a list of areas and their neighbors known as a contiguity table. The table is then used to sequentially aggregate areas into larger regions until predetermined criteria are met.