How every number in a PropDossier report is verified
PropDossier verifies a flip in six steps: cross-check listing against county records, let the county decide conflicts, build ARV from arm's-length closed comps, derive four reference prices, stress-test them in a 3×3 grid, and re-derive everything in an independent review.
Bad flips start with one unchecked input. Every sample report follows this process.
- 1Dual-source check
- 2County decides
- 3Comps line by line
- 4Price ladder
- 5Sensitivity grid
- 6Independent review
1. Dual-source verification
L = listing · C = county assessor and recorder (e.g. Pierce County ATIP).
Listings are written to sell; county data exists for tax and is usually more conservative.
Portals mislabel tax years and show internal transfers as sales.
2. County records decide
Conflicts go to the county number; both are shown. Case from the sample report.
Comps and renovation budget both scale with area. Pricing a concrete basement as finished space is simply wrong.
County records miss unpermitted additions and carry stale condition ratings: tiebreaker, not gospel.
3. Comparable sales, line by line
- Arm's-length closed sale (recorder-verified) ✓ used
- Foreclosure / trustee transfer ✗ excluded
- Partial-interest transfer ✗ excluded
- Family transfer, estate, nominal quitclaim ✗ excluded
- Pending or active listing ✗ excluded
- New construction ⚠ reference
ARV comes only from closed, county-verified sales of renovated homes, never from portal estimates, which value the house as-is and hide their inputs.
A comp that matches on paper but hides a finished basement or another school area.
4. Four reference price points
Reference lines, not offer advice. Cost assumptions are stated in each report; internal parameters stay private.
A single "worth X" hides the real question: at what price does this stop being a deal?
Forgetting holding costs, and that selling costs are charged on ARV, not purchase price.
5. Sensitivity matrix
Purchase price fixed at asking. Center = base case; bottom-left = realistic worst case. Green center, red bottom row: everything must go right.
It asks "how many things must go right?" rather than "is the base case good?" The sample report adds a drag calculator.
Reading only the center cell; treating the optimistic column as the plan.
6. Independent review
- Recompute every figure from scratch
- Reopen every county and listing page
- Re-test that every comp still qualifies
- Click every source link
- Label anything unverifiable "unverified"
Collection is automated; review and judgment calls are human. Every material error we have caught was caught here.
Re-reading the report instead of re-opening sources. Re-derive, don't proofread.
What we don't publish. Internal cost-model parameters and anything that amounts to buyer strategy for a specific property. The method is public; the calibration is not.
Please read. PropDossier reports are provided for informational and educational purposes only. They are not an appraisal, not a valuation opinion, not brokerage services, and not investment, legal, or tax advice. They are based on public records and listing data, which may contain errors, and they do not include a physical inspection of the property. Verify all figures independently and consult licensed professionals before making any real estate decision.
Buying a renovated house rather than underwriting one? See 5 things to check before you buy a flipped house. Learn more about who we are on the About page.
Related reading
Sources
- Pierce County Assessor-Treasurer Information Portal (ATIP) — example county assessor and recorder portal: building, sales, deed type, assessed value and taxes by parcel; checked 2026-08-27.
- City of Tacoma permit portal (Accela) — example city permit portal: permit history and inspection status by address; checked 2026-08-27.
- Northwest MLS (NWMLS) — the MLS whose listing data appears on public portals for Washington addresses; checked 2026-08-27.
FAQ
Why not just use Zestimate or the Redfin Estimate for ARV?
Portal estimates are automated models built on listing data for the house as it stands today. They cannot tell a renovated house from an original-condition one, they inherit listing errors such as basement area counted as living area, and they do not show which sales they relied on. ARV in a PropDossier report comes from closed, county-verified sales of renovated homes, adjusted line by line, with every comp linked so you can check it.
What counts as a valid comp?
A closed sale, not a pending or active listing, of a similar property type in the same area, within a recent window, with the deed verified as an arm's-length transfer in county records. Foreclosure transfers, partial-interest deeds, family transfers, and new construction are excluded or marked for reference only. Each comp is then adjusted for size, age, condition, lot, bathrooms, and date of sale.
Do you verify permits?
We check the permit history available in public county or city records and note what we find, such as whether a remodel or addition appears to have been permitted. We do not inspect the property, so a permit record tells you what was filed, not what was built. Where a record is unclear or unavailable, the report says so.
Is a PropDossier report an appraisal?
No. A PropDossier report is a due-diligence document based on public records and listing data. It is not an appraisal, not a valuation opinion, and not a substitute for a licensed appraiser, inspector, attorney, or real estate broker. Lenders will not accept it in place of an appraisal.
Where does the data come from?
Listing data comes from the MLS as displayed on public portals. Property facts, ownership, deed history, assessed value, and taxes come from the county assessor and recorder. Permit history comes from county or city permit portals. Every key fact in the report links to the page it came from, and anything we could not verify is labeled as unverified.
Want this done for a specific address?
Get a free sample analysisPublished 2026-08-23 · Updated 2026-08-23 · PropDossier Research