Methodology
How we measureand what we evaluate against.
A valuation model is worth exactly as much as its evaluation. This page documents what our engine actually predicts, how we verify it after every retraining, and which limits we know about — including a public model card, with real numbers, as an example.
01 · What we measure
The target is the selling price,not the initial asking price.
A common — and legitimate — objection to listing-based models: an advertised price is not a transaction. That is why our training and evaluation target is not the initial asking price, but the price level at which the market actually closes.
Target definition
The engine predicts the market price of an equivalent vehicle at selling level: the last observed price of a listing before it disappears from the market, after its full sequence of price drops. It is the best observable proxy for the closing price at market scale.
In-house sold tracking
We detect sales with our own tracking: every listing is monitored daily and, when it disappears in a sustained way, it is recorded as a sale event together with its complete price-drop curve and time on market. This signal is calibrated per market to each country’s typical stock rotation.
Honesty about the asking-to-close gap
A listing’s initial price is not the price the deal closes at; the gap varies by country, segment, and vehicle age. We do not ignore it: the training pipeline explicitly models the price trajectory down to the listing’s disappearance, and evaluation is done against that last price — not the first one.
02 · How we measure it
Blind backtestingagainst observed sales.
The metrics we publish come from a fixed protocol, executed automatically after every retraining, in each of the 13 countries.
Blind valuation
In the backtest, the model values each vehicle without seeing the listing price: it receives only brand, model, trim, year, mileage, fuel, and power — exactly what it would receive from a client. The prediction is then compared with the last price observed before the sale.
Stratified sampling
The evaluation sample is stratified over recorded sales to reflect the real composition of the market — by brand, segment, and fuel type — instead of concentrating on the easy vehicles.
Published metrics
We report MAPE with a confidence interval, bias (mean signed error), the share of valuations within ±10%, ±15%, and ±20% of the real price, and R². No single metric tells the whole story; we publish the set.
Continuous validation with a regression guard
After every retraining, each country’s accuracy report is regenerated and an automatic guard compares it with the previous cycle: if a country degrades beyond the threshold, an alert fires and the deployment is reviewed before the new model is served.
03 · Public model card
A real example:Spain, blind backtest.
Metrics from the current accuracy report of the Spain model, generated on 21 August 2026 after the latest retraining. Protocol: blind valuation against 5,995 observed sales, a stratified sample of the mainstream market. These are the same numbers our own team sees — no cherry-picking of the best cycle.
| Metric | Value | |
|---|---|---|
| Sales evaluated (n) | 5,995 | stratified sample over recorded sales |
| MAPE | 11.7% | 95% CI: 11.3 – 12.1 |
| Mean bias | +1.0% | 95% CI: +0.6 – +1.5 |
| Within ±10% | 56.6% | |
| Within ±15% | 74.0% | |
| Within ±20% | 84.1% | |
| R² | 0.94 |
The honest reading: in blind valuation — without seeing the listing price — market-level error sits around 11–12%, with near-zero bias, and 3 out of 4 valuations fall within ±15% of the real selling price. With the listing price as an input (the repricing use case), the error is substantially lower.
Model cards for all 13 countries, with breakdowns by brand, segment, and vehicle age, are available under NDA. Request per-country model cards.
04 · Anchoring to new-vehicle price
Every valuation startsfrom the new-vehicle price.
The architecture is hierarchical: the model does not predict a price in a vacuum — it predicts depreciation relative to the new price of the specific trim. That requires a solid new-price catalog per market.
Official sources and sealed catalogs
The new-price catalog is built per market from official sources — public registries and bodies such as the BOE in Spain, OFV in Norway, or Skatteverket in Sweden — plus sealed historical catalogs by trim. We do not depend on a single origin per country.
Canonical normalization
Brand, model, and trim are normalized to a canonical catalog shared across the 13 countries, with prices in local currency and EUR. Every trim is anchored to its new price, making depreciation curves comparable across markets.
Why it matters
Anchoring gives the model a stable reference when market data is scarce — rare trims, small markets — and prevents a local bias in active stock from dragging the valuation.
05 · What we do not do
Known limits,stated upfront.
We would rather you present the system’s limits to your risk committee in our own words than have them discovered in production.
No personal data
We do not collect, store, or sell personal data of buyers or sellers. The object of analysis is the vehicle and its price — not people.
No literal listing content
Our data products deliver structured, aggregated market information — prices, specifications, movements — never the literal content of source listings (texts, photographs).
Coverage varies by country
Data depth is not uniform: large markets carry more signal than small ones, and per-country accuracy varies accordingly. Per-country model cards exist precisely so that difference is visible before you sign.
More uncertainty on older vehicles
Above ~8 years of age, real market dispersion grows — condition, history, and maintenance outweigh the spec sheet — and model error grows with it. We reflect that in the intervals rather than hiding it in the average.
Next step
The methodology is public. The data is under agreement.
If you need the market database, the licensed engine, or the full per-country metrics, tell us your case and we reply within 24h.