Online filtering selects training problems during optimization according to their current difficulty or learning signal. It targets prompts whose sampled completions provide useful differences in policy-gradient outcomes. section 7.3.3
A practical filtering pipeline can:
- Sample multiple completions for each prompt, verify correctness, and estimate its current success rate. section 7.3.3
- Prefer problems with mixed outcomes, such as 20–80% correctness, rather than prompts solved always or never. section 7.3.3
- Filter questions within each batch or schedule harder problems later through curricula and data schedulers. section 7.3.3
Batch-level filtering
For each training prompt, sample 16 completions and verify them. Retain prompts whose current correctness rate supplies contrasting outcomes, then assemble the optimization batch. section 7.3.3
