Hanna Test

The Hanna test, derived from Hanna v. Plumer (1965), is a framework within the broader Erie doctrine for resolving conflicts between Federal Rules of Civil Procedure and state procedural rules in diversity cases. It provides a more straightforward analysis than the unguided Erie approach used when no Federal Rule is directly at issue.

The test has two steps. First, the court determines whether a Federal Rule of Civil Procedure is "sufficiently broad to cover the point in dispute" — that is, whether the Federal Rule directly addresses the same issue as the state rule. If so, there is a direct conflict and the Federal Rule applies, provided it is valid.

Second, the court assesses the validity of the Federal Rule. Under the Rules Enabling Act, Federal Rules must not "abridge, enlarge, or modify any substantive right." This is a lenient standard — a Federal Rule is valid as long as it is "arguably procedural" and does not directly regulate substantive rights. In practice, virtually all Federal Rules survive this test.

Hanna v. Plumer itself involved a conflict between Federal Rule 4(d)(1), which permitted service by leaving documents at the defendant's home, and a Massachusetts statute requiring in-hand service. The Court held that the Federal Rule controlled because it was on point and valid under the Rules Enabling Act.

The Hanna test also applies to Federal Rules of Evidence and other rules promulgated under the Rules Enabling Act. It does not apply to judge-made federal procedural practices that are not codified in a Federal Rule — those are governed by the unguided Erie analysis.

After Shady Grove Orthopedic Associates v. Allstate (2010), the application of Hanna became more nuanced. Justice Scalia's plurality opinion interpreted Federal Rule 23 broadly to cover class certification requirements, while Justice Stevens's concurrence argued that a Federal Rule should not be read to govern an issue if doing so would violate the Rules Enabling Act by altering state substantive rights.

On exams, the Hanna test is the first step in any Erie analysis: if a Federal Rule directly conflicts with the state rule, apply Hanna. Only if no Federal Rule is on point does the analysis proceed to the unguided Erie framework.