| --- |
| license: other |
| license_name: mixed-upstream |
| license_link: https://github.com/OpenBallast/ballast |
| language: |
| - en |
| pretty_name: Ballast eval sets |
| size_categories: |
| - 10K<n<100K |
| tags: |
| - question-answering |
| - factuality |
| - hallucination |
| - rag |
| configs: |
| - config_name: matrix_probes |
| data_files: matrix_probes.parquet |
| - config_name: halluc_probes |
| data_files: halluc_probes.parquet |
| --- |
| |
| # Ballast eval sets |
|
|
| The probe sets behind the [Ballast](https://github.com/OpenBallast/ballast) |
| measurements. Two files: |
|
|
| - **`matrix_probes.parquet` — 50,147 factual questions** (recall), each with a |
| gold answer, alias set, 7 type-matched distractors, and — where resolvable — |
| a Wikidata subject Q-id linking it to the |
| [Ballast T0 corpus](https://huggingface.co/datasets/OpenBallast/ballast-t0) |
| (90.5% linked at full corpus). Measured on two model families: Gemma-4 |
| (E2B/E4B/12B) and Qwen3.5 (0.8B/2B/4B/9B), plus a bf16/fp8/nf4 quantization |
| sweep. |
| - **`halluc_probes.parquet` — 43,137 hallucination probes** (beyond recall), |
| 98.3% entity-linked, run over seven (model, quant) cells. |
|
|
| ## Recall probes (`matrix_probes`) |
| |
| | source | origin | notes | |
| |---|---|---| |
| | `popqa` | PopQA | native subject Q-ids + popularity; the primary instrument | |
| | `wikidata` | self-generated from T0 | rank-stratified, uncontaminated by construction, regenerable | |
| | `simpleqa` | SimpleQA | typed distractors from answer_type × topic | |
| | `nq_open` | Natural Questions (open) | entity-linked via normalized n-gram match | |
| | `triviaqa` | TriviaQA (rc.nocontext) | linked via wiki-title hints + spans | |
|
|
| ## Hallucination probes (`halluc_probes`) |
| |
| | family | n | what it tests | |
| |---|---|---| |
| | `hop2` | 24,320 | self-generated 2-hop compositions from T0 ("where was the director of this film born?") — the answer exists only through a join across two evidence lines, so copy-extraction cannot work. Includes a 3,200-probe adversarial subset (`adversarial=true`) where the competing join path's answer is also present in evidence. | |
| | `unanswerable` | 12,000 | 9,600 `absent_prop` (the property was never recorded) + 2,400 `false_premise`. Every candidate answer is false; any confident pick is a fabrication. | |
| | `wikimulti` | 6,000 | 2WikiMultiHopQA compositional + inference questions, both hops entity-linked. | |
| | `truthfulqa` | 817 | TruthfulQA mc1 as a control family: grounding is expected to leave it unmoved. | |
| |
| What they showed (full analysis in the |
| [thesis](https://github.com/OpenBallast/ballast/blob/main/THESIS.md)): |
| grounding collapses multi-hop hallucination in all 21 family×cell readings |
| (3–20×, monotone in corpus level), but on unanswerable probes fabrication |
| *rises* with corpus coverage in all 7 cells — evidence that mentions the |
| question's entities without containing an answer suppresses exactly the |
| abstentions that were correct. The TruthfulQA control is imperfect: 3 of 7 |
| cells hold within the 2% margin. |
| |
| ## Schema |
| |
| Both files: `question_id`, `source`, `question`, `prop`, `subj`, `subj_qid`, |
| `gold`, `gold_aliases[]`, `distractors[]`, `s_pop`, `pop_decile`. |
| `halluc_probes` adds `family`, `subfamily`, `adversarial`, `bridge_qid` |
| (the join entity for 2-hop probes). |
|
|
| ## Intended use |
|
|
| Logprob choice scoring: score gold + distractors under the same prompt, |
| prediction = argmax length-normalized answer logprob, confidence = softmax mass on |
| argmax, abstain below 0.5. Grounded condition prepends the subject's rendered |
| evidence block from T0 at a chosen level (2-hop probes prepend both hops' |
| blocks). Two passes (no corpus / full corpus) compose exactly to every corpus |
| level via the subject's rank bucket — see the |
| [methodology](https://github.com/OpenBallast/ballast/blob/main/THESIS.md). |
|
|
| ## Contamination stance |
|
|
| Models have seen the upstream benchmarks' sources in pretraining. The `wikidata` |
| recall probes and the `hop2` compositions are uncontaminated by construction |
| (generated from the corpus, not the web). The headline quantity |
| (grounded − ungrounded delta) is contamination-conservative: pretraining |
| exposure inflates the ungrounded floor, shrinking the measured gain. |
|
|
| ## Licenses |
|
|
| Upstream sets keep their upstream licenses (PopQA/TriviaQA/NQ/2WikiMultiHopQA/ |
| TruthfulQA: research-standard open licenses; SimpleQA: MIT). The self-generated |
| `wikidata` and `hop2` probes are CC0. Check upstream terms before commercial |
| use of those subsets. |
|
|
