Small-cell re-identification risk

privacy

A cell with very few observed individuals (e.g. 1-3) can be cross-referenced with public or other data sources to re-identify a specific person, even without any single field being personally identifiable on its own.

Detection

Per-cell unique-individual count below a defined re-identification risk threshold (commonly k=5 or higher depending on sensitivity).

Mitigation

Suppress or roll up any cell below the k-anonymity threshold to a coarser resolution
Apply the same suppression rule consistently across all output cuts (time, cell, segment) of the same underlying data

Affected conversions

Point → H3 exact
Raster → H3 approximate