Multistate Bar Examination Practice Question

The correct answer is that State B's law applies because the allocation of the burden of proof is considered substantive law under the Erie doctrine. In Erie Railroad Co. v. Tompkins, the Supreme Court held that in diversity cases, federal courts must apply state substantive law but federal procedural law. To distinguish between substance and procedure, courts often apply the 'outcome-determinative test' established in Guaranty Trust Co. v. York. Under this test, a state law is considered substantive if failing to apply it would significantly affect the outcome of the case. The burden of proof is outcome-determinative and is therefore treated as substantive law. Thus, the federal court must apply State B's law on the burden of proof for contributory negligence.