External evidence or evidence that is inadmissable or not properly before the court, jury, or other determining body.
Several factors are relevant to determining whether the alleged introduction of extrinsic evidence constitutes reversible error:
(1) whether the extrinsic material was actually received, and if so, how; (2) the length of time it was available to the jury; (3) the extent to which the jury discussed and considered it; (4) whether the material was introduced before a verdict was reached, and if so, at what point in the deliberations it was introduced; and (5) any other matters which may bear on the issue of . . . whether the introduction of extrinsic material [substantially and injuriously] affected the verdict. Bayramoglu v. Estelle, 806 F.2d 880, 887 (9th Cir.'86), quoted in Jeffries v. Blodgett, 5 F.3d 1180, 1190 (9th Cir.'93) (noting that "none of these factors should be considered dispositive"). When assessing prejudice claims in juror misconduct cases, this court also places great weight on the nature of the extrinsic evidence introduced. See Jeffries, 5 F.3d at 1190-91; Dickson, 849 F.2d at 406-07; Marino, 812 F.2d at 506.
'[R]eversible error commonly occurs where there is a direct and rational connection between the extrinsic material and a prejudicial jury conclusion, and where the misconduct relates directly to a material aspect of the case.' Marino, 812 F.2d at 506