Method / Source acceptance
A useful source comparison starts with the fields your acquisition workflow needs. Test identity, geographic scope, vintage and access separately, then decide which source can support a bounded next step. A source can be valuable for locating records while still being unsuitable for bulk joins or redistribution. This guide gives your team a repeatable acceptance method without presenting a nationwide coverage ranking.
Use the fictional worked example and editable worksheet to apply this method to your own documents.
The useful distinctions
Decide whether your working row represents a parcel, building, address, owner or transaction. Census GEOIDs identify geographic areas; they should not be substituted for local property identifiers. Record the local source key and the broader geographic key as separate fields.
Source 1The assessment year, geometry edition and recorded-document date can refer to different periods. A website’s last-modified date does not automatically describe the row you downloaded. Keep the source edition beside each field used in your screen.
Source 1An accessible map is useful evidence of a viewing interface. Before promising a reusable file, inspect export options and the applicable terms for that exact source. Save the restriction and assign a decision owner instead of marking the entire state available.
Observation to next action
| Evidence in the file | What it describes | Next review |
|---|---|---|
| Map visible | A record can be inspected | Check whether the fields can be exported for the proposed purpose. |
| Identifier present | A potential join key exists | Test uniqueness, leading zeros, local boundaries and unmatched rows. |
| Recent page date | The website changed | Identify the actual dataset vintage and each relevant field date. |
Work through the file
Use this sequence with the documents available for your file. Keep a reference with each observation and turn unresolved items into explicit requests.
Write the required geography, row grain and minimum fields at the top of the worksheet. In the fictional exercise, the team wants one row per acquisition parcel, but source B supplies one row per address. List the fields that locate the parcel separately from any owner or contact requirement. Name an acceptable unresolved state before deciding whether a source can support the requested output.
Select a disclosed sample and save the original rows, query and timestamps. Include the cases needed to test the intended join, such as repeated addresses or identifiers with leading zeros, rather than choosing only convenient matches. Record how the sample was selected. This guide supplies no retrieved sample: the two-county exercise is fictional and cannot establish coverage or an observed error rate.
Keep missing keys, repeated identifiers, stale dates and prohibited uses as separate exceptions. In the fictional comparison, do not collapse several parcel rows into one address row merely to produce a match. Ask for the relationship definition and preserve the unmatched records. Assign technical mapping questions to the data analyst and reuse questions to the appropriate source owner or governance reviewer.
Record accepted uses, excluded uses and the next verification owner. A source might be accepted for locating records while its bulk export remains unresolved. Keep that distinction in the handoff rather than labelling an entire state ready. Retain the reviewed mapping, sample and permission evidence together, and reopen the affected check when a query, license, field definition or geographic scope changes.
Before using the output
No. It structures a source-by-source acceptance decision for a defined task. The current edition contains no measured state ranking.
Ask AI to compare supplied field dictionaries, propose a parcel-to-address mapping and flag repeated or unmatched keys. Require the original field names and a reason for each transformation. A data reviewer should test the proposed join, while the governance reviewer accepts the intended reuse. Neither an AI mapping nor one successful lookup establishes statewide readiness.
Record the intended use, required fields, geographic coverage, retrieval date, matching rules and known exceptions. Test a bounded sample and assign a reviewer before using the source in a larger workflow.
From the page to your next task
Build an editable source acceptance and reuse register, retain document references and open decisions, then export your team's working file.
Scope: One review file using the method in the accompanying guide. The example is fictional.
Edition 2026-09-30.1
Evidence and scope
Loudoun County · Checked 2026-09-29
Observed schema lists GIS acreage, legal acreage, plat references and update fields.
US Census Bureau · Checked 2026-09-30
Explains geographic identifiers and their role in joining statistical information at a defined geographic level. This is not a national parcel identifier system.
