Cross-Lingual Safety Gap (CLSG)
Motivation
Safety evaluation is dominated by English-language benchmarks. If a model's refusal behavior, instruction-following, or resistance to harmful requests changes materially when the same intent is expressed in another language, that shift is invisible to a single-language benchmark. CLSG gives that shift a name and a number.
Formula
Where safety_score is a 0–100 aggregate over a fixed test-case set, computed identically for both languages. A positive CLSG means the model was measurably less safe in the evaluation language. An average CLSG across models and evaluation languages can be reported for a single reference language (e.g. English).
Assumptions
- The reference and evaluation variants express the same underlying intent (semantic equivalence).
- The safety scoring rubric is applied identically regardless of language.
- Test cases are representative of the categories they claim to cover, not exhaustive.
- Model outputs are sampled under comparable decoding settings across languages.
Normalization
Safety scores are bounded to [0, 100] before differencing, so CLSG is reported in percentage points rather than a ratio. This keeps the metric interpretable at the cost of not correcting for a category's intrinsic difficulty — a harder category will tend to show larger absolute gaps even at equal relative degradation. We report per-category CLSG alongside the aggregate for this reason.
Limitations
- CLSG has not been validated against human judgment at scale.
- It is sensitive to translation quality and semantic-equivalence screening thresholds.
- A single scalar cannot capture the full shape of behavioral difference (see failure taxonomy in the platform dashboard).
- Comparisons across unrelated language pairs or across different underlying datasets are not meaningful.
Future validation
Planned work includes correlating CLSG against human-annotated safety judgments, testing sensitivity to translation provider and similarity threshold, and publishing inter-annotator agreement statistics once the full VERIAUDIT-500 dataset is human-verified.