Measuring Determinacy Across Jurisdictions

Why it matters

Jurisdictional indeterminacy is the form of genuine ambiguity lawyers meet most often: the same argument wins in one circuit and loses in another. Clients and courts need to know not only whether a question is open, but whether it is open here, and whether the same question is closed next door. A measure that works inside one forum cannot say whether forum choice changes the outcome, or by how much.

State of the art

Splits are tracked by hand, in treatises, certiorari petitions and law review notes. Outcome prediction estimates what a particular court will do, but it conflates the openness of the law with the richness of the features and needs a history of decided outcomes. Pleading standards show how fast the ground moves: state courts of last resort have divided on whether to adopt federal plausibility pleading, some adopting it and others keeping their traditional standards, and the question can be under argument at a state high court while a brief is in draft.

Our partial answers

Ariadne's Thread defines openness as noise-corrected dispersion across lawful judicial postures over a fixed, verified substrate. Its normalizer is absolute, so Z can be computed for a single motion without a reference population. But it was developed for one forum, the New York Supreme Court, Commercial Division, on motions under CPLR 3211 and 3212, and its numerator is panel-relative. A posture panel has to be declared for each forum, the postures that are lawful in one court may not be lawful in another, and comparing Z across forums requires comparable gate schemas and comparably spanning panels. We have not built those.

The five-type taxonomy of genuine ambiguity names jurisdictional indeterminacy as its own type, so a system can flag a split and map which courts hold what. Flagging a split is not the same as measuring how much the choice of forum moves the outcome, and that measurement remains open.