How our numbers are measured

The floor rule

Public labels like “1M+ permits”, “65K licenses”, “2.2M+ parcels”, and “910K recorded sales” are floors: each is published only because the measured count exceeds it (last full re-measurement 2026-08-14). Between refreshes the database grows, so drift can only make these labels more true. A monthly claim-drift monitor re-runs every measurement and raises an alarm if any published claim ever overstates the live database — the failure mode the floor rule exists to make impossible.

Sources and freshness

Permits come from 25 Arizona jurisdictions’ own published records — city and county portals, official monthly reports — each ingested on its real publishing cadence and never scraped past a robots.txt or terms that ask otherwise. Freshness is measured, not asserted: a nightly job computes each jurisdiction’s newest permit and the public coverage table shows that date per source. The same page lists the jurisdictions we can’t cover yet, with the reason — a coverage claim is only honest when the gaps are named too.

Contractor linkage

Linking a permit to the statewide AZ ROC roster is a resolution problem, and we publish the measured result (as of 2026-09-04): at least 61% of permits that name a contractor resolve to a verified license, and at least 39% of all permits resolve overall. The gap between those numbers is structural — several jurisdictions publish permits with no contractor field at all, disclosed per source in the coverage table. Where a name is ambiguous, the resolver stops rather than guesses: an honest blank beats a wrong attribution, because a wrong attribution puts someone else’s name on someone’s work.

Valuations and estimates

Declared valuations come from the permit record. When a source publishes none, we may show a labeled estimate (~EST) — the median declared value of comparable permits in the same work class — and the label never comes off. Placeholder values published by portals themselves ($0, $1) are treated as no-data, not as valuations. Sources with no valuation field are marked “n/p” (not published) rather than filled.

Parcels, owners, and the county rule

Parcel and owner-of-record data come from county assessor rolls, joined to permits on the normalized APN — and always county-scoped, because Arizona counties issue colliding APN formats: a Tucson parcel number must never resolve to a Phoenix owner. Owner mailing data is additionally gated in-product. Every join in the codebase runs through one guarded implementation, so the unsafe version cannot be written.

What we deliberately won’t claim

• No invented statistics — a number appears only if a query produced it, and stat modules hide rather than fall back to a constant when they can’t measure.
• No “every permit in Arizona” — the coverage page names what we pull and what we can’t, with reasons.
• No silent estimates — modeled values always carry the ~EST label.
• No guessed identity links — ambiguous contractor names stay unlinked.

Frequently asked questions