United States · Copyright

U.S. ROSS Training Data Case

ROSS used training materials derived from Westlaw headnotes to develop a legal search tool. The district court found numerous headnotes protectable and rejected the fair use defense. The Third Circuit has accepted an interlocutory appeal.

Court or tribunal
U.S. District Court for the District of Delaware; U.S. Court of Appeals for the Third Circuit
Decision date
10 February 2025
Procedural status
Partial Summary Judgment; Appeal Pending
Case number
No. 1:20-cv-00613;No. 25-2153

01

Factual background & dispute

  • ROSS intended to develop a natural language legal search tool designed to compete directly with Westlaw.
  • Contractors created question-and-answer training materials derived from Westlaw headnotes, which ROSS used to train its model.
  • The dispute involves headnote originality, actual copying, substantial similarity, and fair use.

02

Core issues & judicial focus

  1. Whether curated and edited headnotes qualify for copyright protection
  2. Whether copying headnotes to train a competing legal search tool constitutes fair use
  3. How commercial training purposes and potential licensing markets affect the market harm analysis

03

Judicial finding & holding

  • The district court granted partial summary judgment in favor of Thomson Reuters regarding 2,243 headnotes.
  • The district court determined that the training use was competitive and rejected the fair use defense.
  • The Third Circuit accepted an interlocutory appeal on originality and fair use, leaving the final outcome pending.

04

Practical risk implications

01Legal technology developers must distinguish public judicial opinions from proprietary editorial additions in commercial databases.

02Training data procurement requires verification of source materials, licensing scope, derivative transformation methods, and competitive applications.

03U.S. fair use analysis depends heavily on the specific materials used, product functionality, and empirical market harm evidence.

Court documentsFull judgments and orders1 document

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