Figures / Sources

Thinly populated ZIP prefixes written as 000

The prefixes the engine turns into 000 (SPARSE_ZIP3): the 17 HHS listed from the 2000 Census, together with those a recomputation from the 2010 Census ZCTA populations adds (docs/research/notes/deid-detectors-2026-10-15.md section 7.5).

Updated 15 Oct 2026, from its newest record.

The record it is computed from

Records behind this figure
Record	As stated	Dated	Source
Details that identify together are coarsened and measured	In tables, postcodes are cut to their first part (US ZIP codes to three…	15 Oct 2026	Sweeney, Simple Demographics Often Identify…

Details that identify together are coarsened and measured
As stated
In tables, postcodes are cut to their first part (US ZIP codes to three…
Dated
15 Oct 2026
Source
Sweeney, Simple Demographics Often Identify…

Cited in this guide

HIPAA De-Identification for AI Training: Safe Harbor vs Expert Determination

Each record links to its own page, its source and its permanent copy.

The de-identification standard Every figure