Method / Epistemic Pressure Gauge
Epistemic Pressure Gauge
Schema complete · April 2026 · Atlas Heritage Systems · Forms exist. No runs yet.
Purpose
EPG tracks how a model's verbosity, structure, and hedging behavior shift when asked progressively harder, more ambiguous, or more epistemically loaded questions. After ten or more sessions, the accumulated data produces a pressure-response fingerprint for that model — how it behaves under low load, how it changes under high load, and where it breaks.
EPG complements BSA's stimulus-pair divergence metrics. Where BSA asks "do different models disagree on the same content?", EPG asks "does this model behave differently as the content gets harder?"
Quantitative Metrics
Auto-computed from session output.
| Metric | What it measures |
|---|---|
| Input Char Count | Prompt length in characters |
| Output Char Count | Response length in characters |
| Output Ratio | Response length ÷ prompt length (character-based) |
| Hedging Freq | Count of hedging phrases from the 45-phrase canonical list ("may," "might," "unclear," etc.) |
Qualitative Metrics
Human-assigned. Technician entry required.
| Metric | Values | What it measures |
|---|---|---|
| ELS | 0 (low) → 3 (maximum) | Holistic epistemic load score for the prompt — Technician judgment |
| Resolution Type | Collapsed / Deferred / Confabulated / ActiveRes / SelfDiag | How the model resolved or avoided the epistemic tension |
| Canary Quadrant | VC / VCo / SC / SCo | Where the output falls in ECM behavioral space |
| Structural Complexity | flat / headers / nested | Organizational depth of the response — auto-classified |
| Claim Density | integer | Distinct claims per 500 characters — manual count |
Automation Coverage
Relationship to Other Instruments
EPG shares ECM's quadrant vocabulary. ECM assigns a home quadrant from a single session; EPG tracks whether that quadrant is stable across pressure levels.
BSA measures divergence across an ensemble on fixed stimulus pairs. EPG measures how one model's behavior shifts as prompt difficulty increases. Different axes, complementary signal.
EPG is an ensemble instrument — stopwatch, not thermometer. It measures distance across pressure levels, not trajectory over time under investigator torque. Run independently of BOWL/DRILL/FLIGHT.