What is the legal test for revoking a conviction based on a witness testimony?

986 F.2d 1273, 1278 (9th Cir.1993). Reversal is appropriate only if, viewing the error in the context of the entire record, the impropriety "seriously affect[ed] the fairness, integrity or public reputation of judicial proceedings, or where failing to reverse a conviction would amount to a miscarriage of justice." Id. at 1276. Vouching consists of placing the prestige of the government behind a witness through personal assurances of the witness's veracity, or suggesting that information not presented to the jury supports the witness's testimony. Id., citing United States v. Molina, 934 F.2d 1440, 1445 (9th Cir.1991). Chow admits there was no objection interposed at the time of trial, we thus review for plain error.