Overtraining on fresh data dilutes test set contamination, same rejected paper finds

RylanSchaeffer · x · 2026-10-15

Part 3/8 of Schaeffer's contamination-study thread: like discriminative evals, overtraining on fresh data (beyond Chinchilla-optimal) mitigates test set contamination on generative evals.

The authors attribute this to a dose-response mechanism (published separately): overtraining dilutes the proportion of contaminated pretraining tokens. Charts show the crossover point shifting with model size — from 32 test replicas for 34M models down to 1 for 93M, meaning larger models lose their contamination advantage more readily when overtrained.

Related event: NeurIPS Rejects Study Showing Single Contamination Breaks Evaluation Floor(4 posts)→

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