Gaperon team: benchmark contamination skews evals, yet test-data training may aid generalization

antoine_chaffin · x · 2026-10-13

In a discussion on benchmark contamination, Gaperon team member antoinechaffin argues that contaminated data can yield out-of-domain gains, but this makes results hard to read and in-domain gains should be tagged as such — while staying OOD forever isn't a solution either. Quoting the original post: contamination biases the entire evaluation process, yet training on test data seems to increase models' generalization abilities, a point they made when releasing the Gaperon models.

Related event: Gaperon team finds 24% of MMLU leaked into OLMo-2 training data(2 posts)→

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