## Facts

- A collision in Maine injured Albert E. Sampson and killed the other driver.
- Sampson sued the other driver’s executrix, Bertha B. Channell, in federal court in Massachusetts based on diversity jurisdiction.
- The jury specially found the defendant’s decedent negligent but returned a general verdict for the defendant based on contributory negligence.
- Maine placed on the plaintiff the burden to prove absence of contributory negligence; Massachusetts placed on the defendant the burden to prove the plaintiff’s contributory negligence.
- The district court instructed the jury under Maine’s burden-of-proof rule because the accident occurred in Maine, and entered judgment for the defendant.
- Sampson appealed solely on whether the jury should have been instructed under Massachusetts’s burden-of-proof rule.

## Issues

1. In a diversity action, must a federal court apply state law governing the incidence of the burden of proof when that allocation may affect the outcome?
2. If state law governs the burden of proof, should the federal court apply the forum state’s rule (Massachusetts) or the place-of-injury rule (Maine), as determined by the forum’s conflict-of-laws approach?

## Decision

- The First Circuit vacated the judgment, set aside the verdict, and remanded.
- The court held that, after *Erie*, a federal court sitting in diversity must apply state rules allocating the burden of proof when the allocation is likely to affect the result.
- The court further held that the federal court must proceed as a state court of the forum would, including applying the forum state’s conflict-of-laws rules.
- Under Massachusetts conflict-of-laws practice, Massachusetts would apply its own rule allocating to the defendant the burden of proving contributory negligence; therefore the district court’s Maine-based instruction was erroneous.

## Legal Principles

- In diversity cases, federal courts apply state law on matters that are outcome-determinative; burden-of-proof allocation may be outcome-determinative and therefore must be treated as governed by state law.
- Federal courts may not apply an independent federal common-law rule allocating the burden of proof in diversity actions when state law would allocate it differently.
- A federal court sitting in diversity applies the choice-of-law rules of the forum state to determine which state’s law governs a disputed issue, including issues characterized by the forum as “procedural” for conflict-of-laws purposes.
- When the forum state’s conflict-of-laws rules select the forum’s own burden-of-proof allocation for contributory negligence, the federal court must use that allocation.

## Conclusion

The First Circuit ordered a new trial because the district court used Maine’s burden-of-proof rule on contributory negligence; in diversity, the federal court had to apply the outcome-affecting state rule identified by Massachusetts’s conflict-of-laws approach, which placed the burden on the defendant.


Sampson v. Channell, 110 F.2d 754 (1st Cir. 1940)