Caselaw4

Caselaw4 is a dataset of 350k common law judicial decisions from the U.S. Caselaw Access Project, of which 250k have been automatically annotated with binary outcome labels of AFFIRM and REVERSE.

The court case reports used in the dataset are from New Mexico, North Carolina, Illinois, and Arkansas Courts of Appeal. These Courts hear appeals exclusively from lower courts within their respective states, on matters of domestic state law, and the data for these jurisdictions are freely available. Since each case in Caselaw4 appeals some lower court ruling, the possible outcomes of each case are as follows:

• the previous ruling is kept as is (AFFIRM);

• the previous ruling is changed/annulled (REVERSE);

• some parts of the previous ruling are kept and some are changed (MIXED);

• the appeal is dismissed (a type of AFFIRM).

The data in Caselaw4 are stored in JSON format. In addition to the original metadata about the case name, date, court, judges, cases cited etc., we (a) automatically annotated a subset of 250k cases with the AFFIRM or REVERSE outcome label (with weighted average precision of 95.45%), and (b) manually annotated 500 cases from the New Mexico Court of Appeals with the AFFIRM, REVERSE, or MIXED outcome label as well as with the outcome sentences.