Story 3 · trust by analogy
We don't grade the answer — we grade the evidence
Many production models reason by analogy: to value this house, look at similar recent sales; to judge this claim, look at similar past claims. The prediction inherits its credibility from the supporting cases. So interrogate the support.
Wiggle the input
Below, a toy predictor estimates a value from its k nearest past cases (highlighted). Drag the query point. The trust light doesn't watch the prediction — it watches the support set: if a tiny wiggle in the input swaps out the cases the answer rests on, the evidence was fragile, whatever the number says.
stable evidence
This is a certificate on the evidence, orthogonal to the model: it can ride on
top of any similarity-based system without retraining it. Stable support doesn't make a
prediction right — but churning support tells you, cheaply and before the fact,
that this particular answer isn't resting on anything solid.