ACL Experiments
Use this while the experimental story can still change. The ACL evidence bar is not "beats the baseline once": it is a defensible measurement of a language capability, with the failure modes examined.
Baseline honesty
- Include the strongest cheap baseline: a well-prompted current LLM has become mandatory context for most tasks — a method beating only pre-LLM systems invites the "does this matter now?" review.
- Tune baselines with the same care as your method (same search budget, same data); reviewers explicitly probe for asymmetric tuning.
- Report the trivial baselines (majority class, copy input, retrieval-only) when they contextualize how hard the task actually is.
Evaluation design
- Breadth must match the claim: a "general" claim needs multiple datasets; a cross-lingual claim needs typologically distinct languages, not three Romance neighbors.
- Automatic metrics need justification for generation tasks — pair n-gram or embedding metrics with human or LLM-judge evaluation, and validate any LLM-judge against human labels before leaning on it.
- Fix the evaluation protocol before final runs: dev-set peeking on the test set via repeated submissions is unreportable and unrepairable.
Statistical floor
| Result flavor | Required rigor at ACL |
|---|---|
| Small deltas between systems | Significance test (bootstrap/permutation) or overlapping-interval honesty |
| Fine-tuning results | Multiple seeds; mean and deviation in the table, defined in the caption |
| Prompted-LLM results | Multiple prompt paraphrases and/or samples; sensitivity range reported |
| Human evaluation | Raters per item, agreement statistic (e.g., Krippendorff's alpha), pay disclosed |
| Correlation claims (metrics) | Confidence intervals and comparison against existing metric correlations |
The Responsible NLP checklist (Section C) asks for descriptive statistics and error bars — an experiment plan that cannot fill Section C truthfully is incomplete by construction.
Contamination and validity controls
- Reason explicitly about test-set membership in pretraining data: release dates vs model cutoffs, overlap scans, or held-back fresh test items.
- Watch prompt leakage: few-shot exemplars drawn from the test distribution, instructions embedding label hints.
- For annotation-based data, quantify label quality before measuring models against it; models are now frequently better than noisy gold labels.
Ablations and the mechanism claim
- Each component the abstract credits needs an ablation row; each ablation row needs the same variance treatment as the headline number.
- Prefer ablations that test the explanation (e.g., "gains come from the retrieval step") over combinatorial component sweeps.
- Scale ablation: if a claim is "method X helps," show it at two model sizes or state the single-scale limitation explicitly.
Error analysis as a deliverable
The distinctive ACL expectation: a quantitative error analysis with named categories.
- Sample failures (100-200) from the strongest configuration.
- Induce 4-8 functional error categories; double-annotate a subset and report agreement.
- Report category frequencies for your method vs the best baseline — where do gains actually come from?
- Feed the two most persistent categories into Limitations.
Pre-run design worksheet
textClaim: <one sentence> Datasets: <n, why these, language list> Baselines: <incl. tuned LLM baseline + trivial floor> Runs/variance: <seeds or prompt paraphrases; interval type> Significance: <test, when applied> Human eval: <items, raters, agreement plan, pay> Contamination: <audit method> Ablations: <component -> table row> Error analysis:<sample size, category plan>
Common evidence failures seen in ARR reviews
- Averaging over languages to hide that one language regressed — report the per-language block; reviewers open the appendix table first when a claim says "multilingual."
- Comparing your tuned method against baseline numbers copied from papers that used different preprocessing or splits.
- Treating an LLM judge as ground truth without reporting its agreement with humans on a calibration subset.
- Claiming efficiency without wall-clock, memory, or cost on matched hardware.
- Running the significance test only on the comparison that wins.
- Reporting the best seed as the headline and the mean in the appendix — reviewers call this out by name.
When compute is the constraint
- Pre-register (internally) which single configuration gets the full multi-seed treatment, and make it the headline setting.
- Use paired designs — same items, both systems — so smaller samples still yield tight comparisons and permutation tests apply cleanly.
- Prefer breadth at small scale plus depth at one large scale over a thin sweep of everything; state the choice in the setup section.
- Cache and release intermediate outputs so ablations re-score rather than re-run.
Output format
text[Evidence verdict] convincing / thin / misaligned-with-claim [Baseline gaps] <missing or under-tuned comparators> [Statistical gaps] <variance/significance/agreement omissions> [Validity threats] <contamination/leakage/label-quality> [Highest-value next run] <one experiment>
