Expanding Ukrainian legal tasks in LEXTREME + feedback request

#17
by overthelex - opened

Joel,

Thanks again for merging the Ukrainian judgment prediction subset into LEXTREME β€” glad it fits well.

Two things I wanted to bring up:

1. Paper feedback. I've been running fine-tuning experiments on XLM-R and Legal-XLM-R (base + large) for temporal generalization on Ukrainian court decisions β€” training across three epochs (pre-war, hybrid war, full-scale invasion, 428K decisions). One interesting finding: general-purpose XLM-R outperforms Legal-XLM-R by 7–9 pp, likely due to tokenizer fertility penalties on Cyrillic. The paper cites LEXTREME and MultiLegalPile extensively. Would you be open to a quick look at the draft before submission? Your perspective on the legal model behavior would be very valuable.

2. More Ukrainian tasks for LEXTREME. Beyond judgment prediction, I have several datasets on HF that could become LEXTREME subsets:

  • ua-statute-retrieval β€” statute section retrieval benchmark (already on arXiv: 2605.17639)
  • ua-court-citation-graph β€” citation prediction between court decisions
  • ua-temporal-drift β€” the temporal splits from the paper above

Happy to format these to LEXTREME specs. This would give the benchmark its first Cyrillic/Ukrainian coverage beyond judgment prediction.

3. If there are any legal NLP workshops or communities where this work would be a good fit, I'd appreciate a pointer β€” I'm relatively new to the venue side of the field.

Best,
Volodymyr

P.S. We also have a pipeline for 17.5M Indian court decisions (Supreme Court + 25 High Courts, 1950–2026) from the AWS Open Data Registry (CC-BY-4.0). Once the HF dataset is published, Indian judgment prediction could be another LEXTREME task β€” a major underrepresented jurisdiction with both English and vernacular language coverage.

Hi Volodymyr,
Thanks for the message.

  1. Yes, happy to look at it.
  2. Retrieval seems out of scope for LEXTREME unfortunately. How do you represent the citation prediction task?
  3. NLLP at EMNLP (https://2026.emnlp.org/calls/workshops/) could be a good venue. There might be a next edition of the DMAIL at ICDM workshop (https://dmail-workshop.github.io/DMAIL2025/) as well. And lastly there is ICAIL (https://site.smu.edu.sg/icail-2026), but the conference is soon, so you would need to wait for next year.

Hi Joel,

Sorry for the delayed follow-up β€” been heads-down running experiments. Two things:

1. Temporal drift paper (draft)

The paper is ready for your review. This is still a working draft, but the experiments and analysis are complete. Since my last message, we've expanded it significantly with two new experimental sections:

Section 5.5 β€” Continual Learning. Sequential fine-tuning across the three Ukrainian epochs. Key finding: chronological CL (pre-war β†’ hybrid β†’ full-scale) eliminates catastrophic forgetting for general XLM-R β€” pre-war F1 is fully retained (+1.8 to +6.2 pp) while full-scale gains +16.5 to +19.0 pp. Reverse-chronological CL causes severe forgetting (βˆ’12.2 to βˆ’14.3 pp). Legal-XLM-R forgets in both directions, suggesting legal-domain pretraining produces temporally fragile representations.

Section 5.6 β€” Cross-Jurisdictional Temporal Transfer. We use Swiss Judgment Prediction as a foreign-jurisdiction source, extending Cross-X to the temporal dimension. SJP pretraining lifts all Ukrainian epochs by +3 to +10 pp, but the forward degradation magnitude is unchanged (20.3 vs 21.3 pp). Temporal drift is orthogonal to cross-jurisdictional transfer.

The paper is 17 pages, 5 experiments, 6 tables, 5 figures. Draft PDF attached below. We'd particularly value your perspective on:

  • The Legal-XLM-R finding (lower absolute but more temporally uniform -- a trade-off that could potentially be exploited)
  • Whether temporal splits of SJP (2000--2020) could replicate the drift pattern in Swiss data -- this would make it a bilateral cross-jurisdictional temporal study
  • Venue fit -- you mentioned NLLP at EMNLP, which seems ideal

2. Citation prediction task format

The most natural LEXTREME-compatible framing would be multi-label statute prediction (MLTC): given a court decision's facts section, predict which statutes (by article number) the court will cite in its reasoning. We'd limit the label set to the top-N most frequently cited statutes to keep it tractable.

The underlying data comes from our co-citation graph (overthelex/ua-court-citation-graph, 2.3M edges from 99.5M decisions). We can extract (facts_text β†’ cited_statutes) pairs and format them as MLTC.

An additional dimension: the cited statute set evolves across temporal epochs (new Criminal Code articles post-2014 and post-2022), so this task would naturally combine citation prediction with temporal drift.

Would MLTC with top-N statutes work for LEXTREME, or do you have a different format in mind?

Best,
Volodymyr

Draft PDF: temporal-drift-legal-nlp-draft-2026-05-23.pdf

17 pages, compiles cleanly. Numbers are from actual training runs (MLflow), not placeholders. Still a draft β€” happy to iterate based on your feedback.

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