The utility of Zip4 codes in spatial epidemiological analysis.

Area of Science:

• Public Health
• Geospatial Analysis
• Data Privacy

Background:

• Effective public health interventions require fine-scale geographical data.
• Spatial privacy and confidentiality are critical barriers to data sharing among institutions holding health data.

Purpose of the Study:

• To evaluate the utility and risks of using Zip4 codes for sharing fine-scale spatial health data.
• To assess the balance between privacy preservation and analytical precision using Zip4 codes.

Main Methods:

• Utilized Zip4 codes in the context of a near-real-time spatial response to an emerging health threat.
• Conducted spatial analysis experiments comparing Zip4 data with other aggregation units (street lines, census block groups).
• Assessed spatial anonymity using the k-anonymity metric.

Main Results:

• Zip4 centroids are located within 150 meters of the actual address 99% of the time in urban areas.
• Zip4 data provide more insightful geographic output compared to street lines and census block groups.
• Zip4 centroids present a higher risk to spatial anonymity, with 73% of addresses having a k-anonymity value less than 5.

Conclusions:

• Zip4 codes enable data sharing for spatial analysis with enhanced precision.
• The use of Zip4 codes carries a significant risk of compromising spatial anonymity.
• Researchers and analysts must be aware of these confidentiality risks when using Zip4 data.