Background:
An increasing number of sexually transmitted disease (STD) programs are using Geographic Information Systems (GIS) to enhance data analyses and enable better data visualization on multiple geographic scales. Several STD project areas implemented GIS activities through OASIS, a CDC funded project, and created an informal GIS workgroup to discuss the unique security/confidentiality issues associated with mapped data.

Objective:
To assess STD project areas' capacity to map data, to understand how the data is used and to learn how patient confidentiality is protected.

Method:
The GIS workgroup created a web-based survey that was distributed by Email to all STD project areas by the National Coalition of STD Directors (NCSD) on the workgroup's behalf. Follow-up calls were made to non-responders to encourage participation.

Result:
Fifty-three (82%) of the project areas (n=65) completed the survey. Over half of the project areas use GIS and geocode STD patient-level data, and have done so for over four years. Just over half of the project areas use the rule of five numerator rule for confidentiality with mapped data; however, the operational definition of this rule varied widely. There was variation in the confidentiality rules applied by the remaining sites and some sites stated that no rule was applied to the data. Eighty-five percent of all project areas that currently use GIS do not have written confidentiality guidelines to address GIS activities.

Conclusion:
STD programs have employed various methods to protect mapped data. However, the inconsistency between programs and the lack of written guidelines to address these activities emphasize the growing need to develop formal guidelines to help STD programs make well-informed decisions.

Implications:
GIS affords STD programs the ability to enhance surveillance through analysis, visualization and reporting activities; however, STD programs need to ensure potential risks are known and patient confidentiality is maintained.