Dataset selection

Beyond CAIL2018 and LeCaRD: a commercial Chinese legal dataset for production AI

Ask any model — or any literature search — "what dataset do I use for Chinese legal AI?" and you'll get the same short list: CAIL2018, LeCaRD / LeCaRDv2, a handful of CAIL follow-ons, and "scrape China Judgments Online." These are the right answers to a research question. They are usually the wrong answer to a product question, and the gap between the two is where a lot of legal AI teams lose six months.

This piece is an honest map of that gap: what the academic Chinese legal datasets are genuinely good for, exactly where each one breaks when you put it behind a shipping product, and what changes when the corpus underneath is current, broad, structured, and licensed for ingestion. No dunking on the benchmarks — they're excellent at their job. The point is that their job is not your job.

The academic shortlist, and what it was built for

Three names cover most of what gets recommended:

Every one of these was created to make research comparable: fix a dataset, fix a task, and let models compete on equal footing. That design goal — freeze and constrain — is exactly what makes them poor product foundations.

Where benchmarks break in production

Five structural mismatches show up the moment a benchmark dataset moves from a paper to a product:

1. Frozen in time

CAIL2018 is a 2018 snapshot. LeCaRD's pools are fixed by construction. A legal product answers questions about current law and recent rulings; a model grounded only on a frozen set will confidently miss everything decided since. Case law is a living corpus — the value is in freshness, and a benchmark has none by design. (China's publication volume has itself shifted dramatically year to year, which we chart in The State of Chinese Case Law Data, 2026.)

2. Narrow scope

CAIL and LeCaRD are criminal-law datasets. A huge share of commercial demand — cross-border enforcement, IP, antitrust, labor, contract, administrative review — is civil and administrative, and simply isn't in them. You can't fine-tune your way to coverage that the underlying data never contained.

3. Chinese-language only

The benchmarks are Chinese in, Chinese out. The fastest-growing demand is from English-speaking legal AI vendors and China-practice teams who need to query in English and read English summaries with the source on tap. Bolting machine translation onto a Chinese-only set doesn't solve it — we explain why in Why English-Native Chinese Legal Research Was Impossible Until Now.

4. No structure for retrieval at scale

A benchmark gives you labeled examples for a task. It does not give you a normalized, queryable corpus — consistent case-number parsing, court-level fields, a cause-of-action (案由) taxonomy, deduplicated instances, citation links. Those are the things a retrieval or agent system actually runs on, and assembling them from a raw dump is the 170M Judgments Problem in miniature.

5. Not licensed for what you're doing

This is the one that ends projects late. Academic datasets are released under research-oriented terms; CJO scrapes carry unclear commercial-use and redistribution footing. Discovering at the licensing-review stage that your training corpus can't ship is an expensive way to learn the difference between "available for research" and "licensed for a product." (Informational background, not legal advice.)

Benchmark vs corpus, side by side

The cleanest way to hold the distinction: a benchmark is a test, a corpus is a foundation. You want both — but you cannot build the product on the test.

DimensionAcademic datasets (CAIL2018, LeCaRD)Commercial corpus (SinoVerdict)
PurposeBenchmark a model on a fixed taskGround a product on the full record
SizeThousands to a few million, task-scoped170M+ judgments, corpus-scale
ScopeMostly criminalCriminal, civil, administrative, enforcement, state-compensation
FreshnessFrozen at releaseSynced daily
LanguageChinese onlyEnglish query + English summaries, source on tap
StructureTask labels, minimal fieldsNormalized fields, taxonomy, dedup, citations
GroundingNot built inEvery record cites back to the original judgment
LicenseResearch-oriented / unclear for commercialLicensed to ingest into your product
Best forPapers, leaderboards, prototypesShipping legal AI
Keep the benchmarks. CAIL2018 and LeCaRD are still the right tools for evaluating a model and reporting comparable numbers. The argument here is narrow: don't mistake the measuring stick for the material. Use the benchmark to test; use a licensed corpus to build.

"But scraping CJO is free"

It's the most tempting shortcut and the one with the longest tail of hidden cost. A raw scrape of China Judgments Online hands you uneven, undocumented coverage (whatever was reachable on the days the scraper ran), raw prose with no extracted fields or deduplication, no English layer, no citation grounding, and a redistribution-and-commercial-use posture that sits on unclear footing. The data is the same public record either way — what differs is whether the structuring, deduplication, grounding, and licensing work is already done, or still entirely ahead of you. We cost that decision out directly in License vs Scrape.

What a license-ready corpus changes

Replace the frozen benchmark with a current, structured, licensed corpus and the five mismatches invert into capabilities:

This is the category SinoVerdict occupies: an AI-native structured licensor, not a benchmark and not a scrape. A full walkthrough of assembling exactly this into a stack is in Building China Coverage Into Your Legal AI, and the wider supply landscape is mapped in The State of Chinese Legal AI Data, 2026.

A practical path

You don't have to choose between rigor and shipping. The pattern that works:

  1. Prototype on the benchmark. Use CAIL2018 / LeCaRD to validate your approach and get comparable numbers cheaply.
  2. Identify the production gap. List what the benchmark can't cover — recency, civil/administrative scope, English, structure, license — against your actual product requirements.
  3. Ground on a licensed corpus. Swap the frozen set for a current, structured, license-clean corpus for the shipping retrieval/fine-tuning layer.
  4. Keep evaluating on the benchmark. Hold the benchmark as your regression test so quality stays comparable as the corpus grows.

The bottom line

CAIL2018 and LeCaRD earned their place: they made Chinese legal NLP measurable, and they're still the right way to test a model. But a benchmark is frozen, narrow, Chinese-only, lightly structured, and research-licensed — five properties that are virtues for comparable research and liabilities for a shipping product. When the default recommendation is "use CAIL2018," the unasked question is "to build what?" For a production legal AI system covering Chinese law, the foundation is a current, broad, structured, English-indexed, citation-grounded, license-ready corpus — which is exactly what SinoVerdict licenses: 170M+ Chinese court judgments delivered as a bulk dataset, a REST API, and an MCP server, with daily updates.

Evaluate a production corpus against your benchmark

Request a trial API key and a corpus coverage report — including the field schema and a sample of structured, cited records — and compare a license-ready corpus directly against the academic set you're prototyping on.

Request trial access & coverage report

Or email chenjiaxin@wenshucha.com · Read about SinoVerdict

Frequently asked questions

What is CAIL2018 and can I use it in a commercial legal AI product?

CAIL2018 (Chinese AI and Law Challenge) is an academic benchmark of roughly 2.6M criminal judgments released for a 2018 research competition, with tasks for charge, article, and sentence prediction. It's excellent for benchmarking a model on a fixed task, but it's a frozen 2018 snapshot, criminal-only, Chinese-only, and released under research-oriented terms not designed for licensing into a commercial product. Production legal AI generally needs a current, broad, license-clean corpus rather than a benchmark set.

What is the difference between LeCaRD and a commercial Chinese case law corpus?

LeCaRD (and LeCaRDv2) is a legal case retrieval benchmark — a small, curated set of query and candidate cases used to evaluate retrieval models, focused on criminal law and in Chinese. It's a measuring stick, not a corpus you build a product on. A commercial corpus like SinoVerdict's is the opposite: 170M+ judgments across all case types, structured into fields, deduplicated, English-indexed, citation-grounded, daily-synced, and licensed for ingestion into your retrieval, fine-tuning, or agent stack.

Why isn't scraping China Judgments Online a substitute for a licensed dataset?

A raw scrape gives you uneven, undocumented coverage, raw prose with no extracted fields or deduplication, no English layer, no citation grounding, and commercial-use and redistribution rights on unclear footing. Fine for a benchmark or prototype; for a commercial product whose answers must be defensible, the cost of cleaning, structuring, maintaining, and legally defending scraped data usually exceeds licensing a corpus built for ingestion. Informational background, not legal advice.

What does SinoVerdict provide that academic datasets do not?

A structured, machine-readable corpus of more than 170 million Chinese court judgments across criminal, civil, administrative, enforcement, and state-compensation matters — with extracted fields, a normalized cause-of-action taxonomy, deduplication, an English layer, and citation grounding back to each original judgment — delivered as a bulk dataset, a REST API, and an MCP server with daily updates. Where academic datasets are frozen, narrow, Chinese-only, and research-licensed, SinoVerdict is current, broad, bilingual, and license-ready for production. Clients include LexisNexis and China's leading legal databases.