Off-support ratio (OSR)

A companion diagnostic metric to the respondent coverage gap (RCG), proposed in the same paper (Kumagae & Kaneko, arXiv:2610.30900, Oct 2026). Where RCG asks whether every real human respondent has a nearby synthetic counterpart, OSR asks the reverse: whether generated respondents drift outside the "support" — the range of answer profiles that actually occur among real humans. A ratio above 1 indicates generated respondents landing off-support (implausible combinations of answers); a ratio below 1, combined with RCG above 1, indicates the opposite failure — generated respondents contracting onto a narrow band of typical profiles.

First seen in this vault 2026-10-25; not yet used by any paper outside the one that coined it.

References

• claim-silicon-sampling-llms-split-into-off-support-and-contraction-failure-modes
• Captures: 10-inbox/raw/2026-10-25-outside-arxiv261030900-silicon-samples-match-the-answers-but.md