Researchers: many big-lab model evals only prove a data mixture gap, not capability limits

josephdviviano · x · 2026-11-03

Researcher tallinzen argues that many comparison experiments against big-lab models are particularly pointless when the conclusion amounts to "this big company hasn't yet included this particular kind of data in their post-training mixture." Joseph Viviano agrees: a wave of "model X fails at task Y" evals mostly measure post-training data mix differences rather than real capability boundaries, offering little scientific insight or actionable guidance.

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