Provenance Before Prose: Claim-Locked Reporting for Statistical Text Generation
Organizations: Xidian University
Abstract
Large language models (LLMs) can fluently verbalize statistical evidence, yet statistical reports can still drift numerical values, invert effect directions, or restate thresholded contrasts as categorical effects. We frame these failures as a control problem: the evidence-bearing content of a scientific report should be fixed by structured statistical results rather than sampled during prose generation. We therefore use cross-run reproducibility to stress-test whether report-visible numbers and claims are bound before prose generation. Existing controls operate at the text or slot level; a deterministic hybrid template reproduces only 61.1% of report-visible numerical content across seeds because the LLM still selects which findings and numbers the template renders. We propose claim-locked reporting, a provenance-before-prose protocol that fixes the evidence source, numbers, direction, and allowed language strength of each reportable claim before the LLM writes only connective prose. Across fMRI functional-connectivity reporting and randomized controlled trial reporting on Evidence Inference 2.0, claim-locked reporting improves reproducibility over the hybrid template by 37.4 and 20.5 points, respectively. Blinded human audits support the observed direction-preservation and governance trends. In an fMRI cost analysis with DeepSeek, claim-locked reporting also yields the lowest observed token use and median generation latency.
Figures & tables
| Method | Repro. | Hedge | Strong | Num. |
|---|---|---|---|---|
| Free-form | 32.3 | 0.20 | 2.95 | 0.55 |
| Prompt-only | 26.0 | 0.22 | 1.95 | 0.55 |
| Structured | 22.0 | 0.23 | 1.85 | 0.35 |
| Retrieval | 24.1 | 0.21 | 1.50 | 0.20 |
| Post-hoc verifier | 15.2 | 0.25 | 2.75 | 0.90 |
| Hybrid template | 61.1 | 0.25 | 2.25 | 0.00 |
| Method | Input tok. | Output tok. | Latency (s) |
|---|---|---|---|
| Free-form | 20,603 | 5,432 | 111.9 |
| Hybrid template | 21,213 | 7,069 | 123.9 |
| Post-hoc verifier | 44,434 | 16,687 | 295.2 |
| Claim-locked | 12,482 | 4,209 | 77.3 |
| Cohort | Primary | + covariate | Drop |
|---|---|---|---|
| In-house | 10,041 | 8 | 99.9% |
| HCP comparison | 550 | 0 | 100.0% |
| Method | Repro. | Hedge | Strong | Num. |
|---|---|---|---|---|
| Free-form | 74.7 | 0.24 | 0.03 | 0.27 |
| Prompt-only | 85.9 | 0.11 | 0.01 | 0.25 |
| Structured | 90.0 | 0.15 | 0.02 | 0.25 |
| Retrieval | 73.2 | 0.09 | 0.02 | 0.23 |
| Post-hoc verifier | 74.8 | 0.22 | 0.02 | 0.24 |
| Hybrid template | 79.5 | 0.19 | 0.04 | 0.11 |
| Method | Pres. | Inv. | Unres. | Inv. rate (%) |
|---|---|---|---|---|
| Free-form | 103 | 14 | 3 | 12.0 |
| Prompt-only | 102 | 10 | 8 | 8.9 |
| Structured | 103 | 13 | 4 | 11.2 |
| Retrieval | 102 | 6 | 12 | 5.6 |
| Post-hoc verifier | 98 | 11 | 11 | 10.1 |
| Hybrid template | 102 | 17 | 1 | 14.3 |
| Method | FActScore | SelfCheckGPT |
|---|---|---|
| Post-hoc verifier | 0.856 | 0.840 |
| Structured | 0.855 | 0.846 |
| Retrieval | 0.855 | 0.796 |
| Prompt-only | 0.840 | 0.825 |
| Free-form | 0.835 | 0.831 |
| Hybrid template | 0.770 | 0.812 |
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
| Method | Control level | What is controlled | Remaining LLM decisions |
|---|---|---|---|
| Free-form | Text | General grounding instruction | Claims, numbers, direction, strength, wording |
| Prompt-only | Text | Explicit faithfulness instructions | Claims, numbers, direction, strength, wording |
| Structured | Text | Output structure | Claims, numbers, direction, strength, wording |
| Retrieval | Text | Evidence localization | Claims, numbers, direction, strength, wording |
| Post-hoc verifier | Text | Post-generation revision | Initial claims and realization |
| Hybrid template | Slot | Deterministic slot rendering | Slot content and claim selection |
| Configuration | fMRI Repro. | fMRI Strong | RCT Repro. | RCT Strong |
|---|---|---|---|---|
| Hybrid | 61.1 | 2.25 | 79.5 | 0.040 |
| Builder only | 85.0 | 1.60 | 90.3 | 0.000 |
| Builder + renderer | 98.0 | 1.40 | 100.0 | 0.015 |
| Full claim-locked | 98.5 | 0.75 | 100.0 | 0.010 |
| Target | FC evidence | RCT evidence | Policy action |
|---|---|---|---|
| Numerical support | Statistical results and derived quantities | Trial outcomes and reported statistics | Allow only evidence-supported numbers |
| Direction preservation | Ledger-stored effect direction | Gold direction label | Preserve the resolved direction |
| Entity/source support | Anatomical and behavioral entities | Trial entities and source information | Exclude unsupported entities or sources |
| Inferential scope | Covariate dependence and exploratory findings | Intervention, outcome, and population | Restrict claim scope when required |
| Interpretive strength | Stability and evidential support | Support available in the evidence span | Limit claims to permitted language strength |
| Assessment | Free-form | Hybrid | Claim-locked |
|---|---|---|---|
| Unhedged strong language | |||
| Automatic rule | 2.50 | 1.80 | 0.60 |
| Reviewer 1 | 2.60 | 1.90 | 0.60 |
| Reviewer 2 | 2.40 | 1.70 | 0.50 |
| Reviewer 3 | 2.70 | 2.00 | 0.70 |
| Reviewer 4 | 2.50 | 1.80 | 0.60 |
| Method | Raw flags | Regex FP | Benign | Harmful |
|---|---|---|---|---|
| Free-form | 213 | 17 | 149 | 47 (5.9%) |
| Hybrid template | 89 | 14 | 55 | 20 (2.5%) |
| Claim-locked | 181 | 1 | 180 | 0 (0.0%) |
Evidence-Grounded Generation
Evidence-grounded generation produces answers and documents whose claims are supported by traceable sources.
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