Several states, including New York, have statutes that work as a screening mechanism on malpractice suits requiring plaintiffs to submit an affidavit of merit from a medical professional. Typically, when a state-law claim is brought in or removed to federal court, the Rules of Decision Act1 requires the federal court to apply state substantive law unless the US Constitution, a treaty, or a statute requires otherwise. In Berk v. Choy,2 the plaintiffs brought Delaware state-law claims in federal court under diversity jurisdiction. The US District Court for the District of Delaware dismissed the complaint for failure to adhere to Delaware’s law requiring an “affidavit of merit” to accompany a medical malpractice complaint. The Third Circuit affirmed, but the US Supreme Court reversed.
In Delaware, a plaintiff cannot sue for medical malpractice unless the complaint is accompanied by an affidavit of merit from a medical professional stating that there are reasonable grounds to believe that each defendant has committed medical negligence. If the complaint is not accompanied by an affidavit, the court clerk is required to refuse to file or docket the complaint.
On appeal, the plaintiffs argued that the sufficiency of their federal complaint is governed by F.R.C.P. Rule 8, which requires only “a short and plain statement of the claim showing that [the plaintiff] is entitled to relief.” The Supreme Court agreed, reasoning that the Delaware law would require the plaintiff to produce evidence beyond the factual allegations required by Rule 8. Instead, the court held, Rule 8 displaces state law and sets the ceiling on the information that plaintiffs can be required to provide about the merits of their claims. Ultimately, the Supreme Court held that plaintiffs in federal courts cannot be required to submit an affidavit of merit signed by a third-party medical professional despite contrary state law.
The holding in Berk creates a schism in medical malpractice claims that remain in state court versus those that are removed to or filed in federal court through diversity jurisdiction. It can be anticipated that savvy plaintiff attorneys will shift to pleading in federal court when possible to avoid the upfront costs of retaining a medical professional to file an affidavit of merit in compliance with state law. Importantly, however, the question remains whether the holding in Berk will also apply to affidavits and certificates of merit that are required by state law but are not required to be signed by third parties, such as New York’s CPLR 3012-a, which requires that in a malpractice action, “the complaint shall be accompanied by a certificate, executed by the attorney for the plaintiff.”
If you have any questions regarding the content of this alert, please contact Kaitlyn McClaine, associate, at kmcclaine@barclaydamon.com; Matthew Larkin, Torts & Products Liability Defense Practice Area chair, at mlarkin@barclaydamon.com; Tom Cronmiller or Sanjeev Devabhakthuni, Professional Liability Practice Area co-chairs, at tcronmiller@barclaydamon.com and sdevabhakthuni@barclaydamon.com; or another member of the firm’s Torts & Products Liability Defense or Professional Liability Practice Areas.
128 U.S.C. § 1652.
2No. 24-440, 2026 U.S. LEXIS 497 (Jan. 20, 2026).