The core idea
Instead of relying only on a formula, gather two groups of real listings for your same year/make/model/trim: vehicles with a clean title history, and vehicles with a disclosed accident/repair history (visible on a Carfax/AutoCheck-style report). Compare the two groups' prices directly — the gap between them is real market evidence of diminished value for your specific vehicle, in your specific market.
How to build a usable comparison
- Search for 4 or more listings in each group if possible — clean-history and accident-history.
- Match year, mileage range, and trim as closely as you can between the two groups.
- Record price, mileage, and a link/date-checked for every listing.
- Enter both groups into the Diminished Value Baseline calculator's market-evidence worksheet.
Worked example. Clean-history group: 5 listings, median $21,400. Accident-history group: 4 listings, median $19,600. The median gap of $1,800 is real evidence for your specific market — distinct from, and potentially different than, a 17c-style formula result for the same car. The calculator only reports a median gap when both groups have a sufficient sample size; with fewer listings, it labels the comparison as limited rather than presenting a false sense of precision.
Why sample size matters
A comparison built from one listing in each group could easily reflect those two sellers' pricing quirks rather than a real market pattern. More listings per group make the median and range more representative — which is why the calculator flags small samples as limited evidence rather than a confident conclusion.
Why this is never averaged with the 17c-style baseline
The formula baseline and the market-evidence comparison answer different questions — one is a disclosed, standardized calculation; the other is what your specific local market actually shows. Averaging them would produce a number that misrepresents both. The calculator always displays them as two separate, clearly labeled outputs.
What this guide cannot tell you
It cannot tell you how many comparable listings are "enough" for your specific insurer's process, or guarantee that a market gap you find will be accepted as your claim's value — only that it's stronger evidence than an unsupported assertion.