Autonomous University of Queretaro

On factual question answering with Qwen3-14B, keeping the generator fixed and training a separate answer selector works better than training the model itself when to abstain. On TriviaQA the selector raises mean coverage from 20.2% under the original calibrated confidence filter to 30.9%, while pooled error among scored answers falls from 23.0% to 14.5%; on NQ-Open its mean utility still stays below always abstaining, so reliable cross-dataset abstention remains unresolved.

On factual question answering with Qwen3-14B, keeping the generator fixed and training a separate answer selector works better than training the model itself when to abstain. On TriviaQA the selector raises mean coverage from 20.2% under the original calibrated confidence filter to 30.9%, while pooled error among scored answers falls from 23.0% to 14.5%; on NQ-Open its mean utility still stays below always abstaining, so reliable cross-dataset abstention remains unresolved.