What is the test for a motion to impeach a jury's verdict in a civil case?

the court's duty to make further inquiries into a claim of juror misconduct.' [Citation.]" (People v. Avila (2006) 38 Cal.4th 491, 605.) Moreover, Code of Civil Procedure section 237, subdivision (b) requires the filing of a declaration to establish good cause for the disclosure of juror information. Here, the accusations of misconduct made by the alternate juror were presented through the unsworn report of an investigator and the juror did not sign the statement. As a result, without considering the merits, we could reject defendant's claim because his motion was procedurally defective.

On the merits, the statements of the alternate juror failed to provide good cause for the disclosure of juror information. She claimed two of the jurors were confused, due to their inability to understand English. As pointed out by the trial court, these jurors were the subject of much questioning by three attorneys during voir dire. We agree with the trial court that it is highly unlikely that the jurors' language difficulties would escape notice. Neither in the trial court nor on appeal did defendant address the trial court's finding on that issue. As to the alternate juror's theory as to why the deliberating jury returned guilty verdicts, her statements were inadmissible. She attempted to explain the subjective reasoning process of the jurors, which is inadmissible under Evidence Code section 1150, subdivision (a). (See People v. Lindberg (2008) 45 Cal.4th 1, 53 [verdict may not be impeached by inquiry into juror's subjective reasoning process].)