The Impact of Data Suppression Rules on Data Access and Re-Identification Risk in Adoption and Foster Care Analysis and Reporting System Annual Files.

One of the most widely used data sources for research on foster care and adoption is the Adoption and Foster Care Analysis and Reporting System (AFCARS). County identifiers in AFCARS are suppressed for all counties with fewer than 1000 cases to prevent the re-identification of vulnerable children, but this also impacts researchers' ability to study smaller communities and analyze how local environments may affect out-of-home placements. This study uses non-public AFCARS datasets to assess, for the first time, how data suppression rules impact data access and re-identification risk. It compares the long-standing 1000-case threshold against a wide range of potential alternatives and finds substantial data access gains coupled with moderate risk increases for thresholds between 400 and 700. Adopting a 700-case threshold leads to a 50% increase in the number of identifiable counties while also keeping the percentage of fostered children who face an elevated risk of re-identification below 1%. Making data from a substantial number of rural counties available to researchers requires much larger threshold changes, which in turn increases re-identification risks.