Surveillance and Data Science Branch of the Division of STD Prevention at CDC

CDC receives requests for nationally notifiable STD data that are collected through NNDSS.  For most data requests, they can point the researcher to the AtlasPlus website where aggregated data sets can be created and downloaded.  If necessary, they also create specific aggregate datasets if the data cannot be found on AtlasPlus.  The data that they share with the public follows suppression rules* that summarized below.  

 

Case counts are aggregated at the county level and can be stratified by 2 of 3 possible factors: age (5 year groups), sex, or race/ethnicity.  We suppress data at any geographic level based on the following 2 conditions:

1.                   20% or more of individuals in a group have the specified disease

2.                   Denominator population is less than 100 (based on Census counts)

To prevent back-calculation of suppressed cells, primary suppression is augmented with complementary (or secondary) suppression in which data for additional groups are suppressed.  

*guidelines are currently being revised but I hope this summary is useful for others who are developing data release guidelines.