Census Data Methodology & Statistical Limits

From original files to one observation

The launch collection uses original U.S. Census bulk files. Selected ACS geographic rows and original PEP CSVs are retained with source URLs, acquisition dates and SHA256 checksums. The 2024 ACS geographic directory and original table shells supply identifiers, labels and universes.

Acquisition is separate from templates. Validation checks exact identifiers, schema cells, duplicate entities, units, nonnegative usable values, valid percentage denominators and source-defined geographic relationships. PEP county/state/national control totals reconcile for all six annual years. Normalized observations feed the page, chart, table and export, avoiding separately maintained figures.

Different periods remain different

ACS five-year estimates describe 2020–2024, not a point-in-time observation for 2024. Publication was January 29, 2026. PEP population history uses annual July 1 observations from Vintage 2025, with national/state publication January 27 and county publication March 26, 2026. Website acquisition and publication are September 30, 2026.

Exact source IDs permit a geographic join but do not make product definitions, boundary vintages or universes identical. ACS records retain 2024 geographic definitions; PEP records retain Vintage 2025. Territory, tribal, city, metro and institution comparisons have not been integrated.

Direct and calculated measures

Counts, medians and means from source tables remain direct observations. Calculated percentages preserve their numerator, denominator and source cells. Rent burden uses B25070_007E through B25070_010E divided by B25070_001E minus B25070_011E. The threshold is at least 30%; the not-computed group is excluded.

Medians cannot be added or averaged to make a regional median. Nonadditive rates and adjusted measures require approved methods. This release offers no custom aggregation, unsupported subgroups or ACS historical trends. Separate state ranking pages provide descriptive point-estimate orderings, not statistical rank intervals. Annual population history uses one consistent PEP vintage.

Uncertainty and missing values

Direct ACS margins of error are retained at the source 90% confidence level. A controlled or unavailable MOE is not invented. Source raw negative sentinels remain visible in raw tables and are excluded from arithmetic. Missing, inapplicable and source-unavailable observations remain separate from a measured zero.

For derived percentages, component MOEs are available but a derived MOE is not calculated. Do not add MOEs or assume every descriptive difference is statistically meaningful. This collection does not conduct significance tests, claim that overlapping intervals prove equivalence, or assign a universal confidence score. PEP has no published sampling MOE here.

Capability and privacy rules

Each indicator specifies supported comparisons, trend suitability, subgroups and aggregation. Only annual PEP history supports a time-series chart in this release. PLACES records are catalog-only and explicitly disallow local trends, overall-health rankings and intervention-effect claims. Education cohorts, fiscal accounting and administrative universes require independent source rules.

Public outputs are aggregate. No suppressed cells are recovered by subtraction or cross-dataset joins. County observations do not establish household or individual circumstances, immigration status, personal risk or the effectiveness of a policy.

Frozen release and update review

The initial release is apd-2026-09-30-r1. Exports include the source version and transformation. Future updates require a new immutable directory, schema/rights review, validation and human review of material methodological changes. Source failure leaves the approved release available; it does not authorize substituting unreviewed numbers.

ADMK Studio S.L. is responsible for the planned monthly source and link checks, with annual ACS/PEP release review. No unattended update scheduler is active. Original producer files remain linked; source discovery records are not presented as completed connectors. See the update log and frozen downloads.