About Gadsden Valuations

Gadsden Valuations Limited builds automated valuation models for the UK residential mortgage market. Our model, Gadsden Meridian, is trained on over 31 million Land Registry transactions and produces valuations with independently testable accuracy — anyone can backtest our model against their own data, free of charge, with no limit.

Our Approach

We believe AVM providers should be judged on published, independently verifiable accuracy metrics — not sales decks. Every metric on this site comes from out-of-sample quarterly bulk testing against Land Registry completions. Our backtest tool lets you verify these numbers yourself.

The Model

Gadsden Meridian is a gradient-boosted decision tree model (LightGBM) using 49 features derived from Land Registry, EPC, and spatial datasets. Per-property confidence scoring maps each valuation to a Fitch-compatible haircut band. Full methodology is published on our Methodology page.

The Company

Gadsden Valuations Limited is registered in England and Wales (Company No. 17079555) and with the ICO (ZC104915).

The company was founded by Andrew Gadsden, who has spent twenty years building web applications — starting with one of the UK’s first ecommerce sites. Gadsden Meridian grew out of a straightforward frustration: AVM accuracy claims in the UK market were unverifiable, benchmarked against surveyor opinion rather than actual sale prices, and impossible for buyers to test independently. The model’s methodology draws on published academic work (Kirchmeyer, Matysiak, Rossini) and the European AVM Alliance’s ESSVM framework. Its accuracy is tested quarterly against Land Registry completions and published in full — including the segments where it performs weakest.

Every metric on this site is independently verifiable. The backtest tool lets you test the model against your own data, on transactions it has never seen, compared to the price that was actually paid.