Opinion ID: 1429600
Heading Depth: 1
Heading Rank: 2

Heading: standard of review

Text: Class certifications are governed by Federal Rule of Civil Procedure 23. As the party seeking class certification, Lozano bears the burden of demonstrating that he has met each of the four requirements of Rule 23(a) and at least one of the requirements of Rule 23(b). [5] See Zinser v. Accufix Research Inst., Inc., 253 F.3d 1180, 1186 (9th Cir.2001). We review the district court's decision regarding class certification for abuse of discretion. See Valentino v. Carter-Wallace, Inc., 97 F.3d 1227, 1234 (9th Cir.1996). The district court abuses its discretion if its certification order is premised on impermissible legal criteria. See Moore v. Hughes Helicopters, Inc., 708 F.2d 475, 479 (9th Cir. 1983). Finally, while we review the district court's factual findings under the clearly erroneous standard, Husain v. Olympic Airways, 316 F.3d 829, 835 (9th Cir.2002), we review the district court's determination of standing and mootness de novo. See Kootenai Tribe of Idaho v. Veneman, 313 F.3d 1094, 1111 n. 11 (9th Cir.2002) (standing); Nat'l Audubon Soc., Inc. v. Davis, 307 F.3d 835, 850 (9th Cir. 2002) (mootness).