K-anonymity thresholds

privacy

Reporting a cell-level metric is only privacy-safe if at least k individuals share that cell/attribute combination; enforcing k only on the cell dimension while ignoring cross-tabulation with other dimensions (age, segment) can still expose small groups.

Detection

Any reporting cut (cell x segment x time) with fewer than k unique individuals, even if the marginal cell total meets k alone.

Mitigation

Enforce k-anonymity on every cross-tabulated cut that will be published, not just the top-level cell total
Suppress or merge categories in any cut that falls below k

Affected conversions

Admin polygons → H3 (weighted crosswalk) weighted
Point → H3 exact
Raster → H3 approximate