# What changes when a model returns a typed judgment?

Jev Decision Lab: Experimental workbench. Published 17 Sep 2026. Question: Where does judgment sit?
Scope: Local workbench · authored business cases
Page: https://jasonlovell.ai/work/jev-decision-lab
Code: https://github.com/jlov7/jev-decision-lab

A local lab for exploring typed answers, probabilities and policy in authored business cases.

## Status

The lab puts a typed Jev judgment and its probability beside the policy code that acts on it, so each can be inspected on its own, using synthetic business cases.

## In practice

Keep a model’s judgment and the policy that acts on it separate, so each can be inspected.

## What I built

A teaching and experiment workbench around TypeSafe’s Jev judgment model, with synthetic cases and inspectable decision records.

## Where the evidence stops

An experimental workbench. Authored cases and owner-recorded observations do not establish business ROI or production readiness.

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By Jason Lovell. Independent work, separate from my role at PwC. I build everything here myself, end to end, with Claude Code and Codex. I write the question and the test first, read the runs, and keep the results that go against me.