Null-Result Asymmetry
Null-Result Asymmetry is a measured tendency to assign a null or negative finding less conclusion-consistent probability than a matched positive finding under otherwise identical conditions. The same system that states a positive result plainly will hedge the corresponding negative one, even when the evidence of absence is clear. This blocks automating clean-bill-of-health work in compliance and review.
Also referred to as: null-result bias.
How it manifests · Measured
Measured directly in our matched-vignette benchmark: holding evidence quality constant and reversing only the direction of the conclusion, frontier models allocated less probability to null findings than to matched positive ones. The gaps ranged from roughly 20 to 57 percentage points, and the asymmetry held in 23 of 24 paired conditions.
Evidence: Asymmetric Burden of Proof
Related terms
- Null-result omission · Canonical epistemic failure modes
- Epistemic failure mode · Core concepts