What is the test for determining whether a single error in a trial is prejudicial to a defendant?

In some cases, although no single trial error examined in isolation is sufficiently prejudicial to warrant reversal, the cumulative effect of multiple errors may still prejudice a defendant. United States v. Frederick, 78 F.3d 1370, 1381 (9th Cir.1996). [W]here the government's case is weak, a defendant is more likely to be prejudiced by the effect of cumulative errors. Id. Our court is particularly sensitive to allegations of prejudice where, as

[662 F.3d 543]

here, the convictions are based on largely uncorroborated testimony of a single accomplice or co-conspirator. United States v. Wallace, 848 F.2d 1464, 1475 (9th Cir.1988).