Cox v. Brown: New and material evidence requires a reasonable possibility of changing the outcome

The veteran sought to reopen previously denied claims for service connection for hypertension and a stomach disorder. The Board had denied reopening, reasoning that the newly submitted evidence did not establish that either condition was present in service or within the applicable presumptive period. On appeal, the Court explained that the Board misstated the legal standard because new and material evidence need not itself establish service connection; it need only create a reasonable possibility of changing the prior outcome when considered with the old evidence and presumed credible. The Court also synthesized the governing reopening framework, reiterating that new evidence must be noncumulative and material to the issue at hand.

Applying that standard, the Court affirmed. The additional records largely showed treatment years after service, and the lay testimony and isolated references to 1976 treatment did not reasonably establish chronicity, service nexus, or compensable manifestation within the presumptive period. The Court emphasized that the veteran’s normal separation blood pressure and the absence of in-service chronic stomach findings made the proffered evidence insufficient to reopen. The case matters because it is a core early Veterans Court articulation of the reopening standard and illustrates how the presumption of credibility at reopening still requires evidence capable of changing the outcome.

New and material evidence is evidence that is not cumulative and, when presumed credible, is relevant and probative enough to create a reasonable possibility of changing the prior outcome; it need not independently establish entitlement.

When seeking to reopen, the focus is on whether the new evidence fills the gap in the prior denial in a way that could reasonably alter the result—not whether it proves the claim outright.

Cox is frequently cited for the reopening standard and for the distinction between the threshold to reopen and the merits stage. It helps practitioners evaluate whether new submissions actually address the missing element from the final denial.

Applying too demanding a merits-style standard at the reopening stage.

A veteran submits only recent treatment records and a statement repeating prior allegations after a final denial for lack of nexus. Under Cox, those submissions may be new, but they are not material unless they could reasonably change the prior denial.

Use Cox to argue that reopening requires only a reasonable possibility of a different outcome, while also using it to defend against reopening when the new evidence is merely post-service treatment or cumulative lay repetition.

Colvin v. Derwinski, Justus v. Principi, Manio v. Derwinski, Rabideau v. Derwinski, Espiritu v. Derwinski