Product · traceability as a design principle

Every number has an origin.

A production system for property valuations under Austrian law (LBG, ÖNORM B 1802-1). A spreadsheet can compute a value. What is hard is the auditable path from data source to signed number — and having the same report come out exactly the same way years later.

1,139 tests green
6 valuation methods
LBG · ÖNORM B 1802-1
No language model does the math

The problem

A value is quickly estimated. The proof is the work.

A valuation has to hold up in court, at the bank and before one’s own profession. What gets examined is not the number but how it came about.

01Numbers without provenance. A markup sits in the spreadsheet, but not where it came from. § 10 LBG demands a justification for every single one.
02Not reproducible. Data moves, indices get revised retroactively. Two years on the same calculation gives a different result — and nobody can say why.
03AI that computes — and gets it wrong. A language model that works out figures itself will invent them convincingly. In a valuation report that is not a blemish, it is a liability.

The methods

Six roads to a value — and the duty to justify the one you took.

§ 9 LBG requires the choice of method to be justified and signed. The system proposes, the valuer decides.

§ 4 LBG

Comparative value

Comparables with justification — the excluded ones appear in the report too, with the reason why.

§ 5 LBG

Income value

Income, operating costs and remaining useful life, including Austrian rent-law regimes.

§ 6 LBG

Asset value

Land and building value kept apart, depreciation derived transparently.

ÖNORM B 1802-3

Residual value

For development land: what the site supports once the project is costed.

ÖNORM B 1802-2

DCF

Cash flows across the holding period, every assumption justified on its own.

§ 2 LBG

Liquidation value

When the economic unit is broken up — plus mortgage lending value under BelWertV for the bank.

The difference

Auditable, not merely plausible.

	AI VALUATION OS	AUTOMATED ESTIMATE
Provenance of each number	●Source and justification carried along	●A result with no path
Re-run years later	●Bit for bit identical	●New data, new result
Who computes	●Deterministic, versioned	●The model estimates
Uncertainty	●Stated — or not claimed at all	●One number, smooth
Who signs	●The human, with logged override	●Nobody

Where it stands

Built and tested.

1.139

tests green

methods, plus mortgage lending value

reference cases with fixed target values

documented decisions

A valuation that brings its own proof.

The system is built and thoroughly tested; what it needs now are valuers as design partners to check it against real, anonymised case files. Deep-dive on request.

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