What is substantial evidence in the context of an administrative review?

Substantial evidence means "more than a mere scintilla", but "less than a preponderance." It means "such relevant evidence as a reasonable mind might accept as adequate to support a conclusion." In determining whether there is substantial evidence to support the [Administrator's] decision, [the court is] required to review the administrative record as a whole, weighing both the evidence that supports and detracts from the [Administrator's] decision.

McAllister v. Sullivan, 888 F.2d 599, 601-602 (9th Cir.1989) (internal citations omitted).