Affirming an order certifying a class in this CLRA action for falsely advertising that defendant’s dog food promoted healthy joints in dogs, the Ninth Circuit holds that the district court did not err in holding that damages were a common issue based on an expert’s report showing how a study could be conducted to determine how much average consumers valued the false joint health statement in selecting food for their pets. The Ninth Circuit held that it was not necessary for the expert to have already carried out that study before class certification. It was enough to show that such a study could be performed and achieve reliable results. The district court did not abuse its discretion in holding that defendant had not rebut the presumption of reliance which arose from the materiality of the false joint health statement. The false statement need not be shown to be the sole source of information on which consumers relied in choosing the dog food; it sufficed if it was a substantial factor in a large percentage of consumers’ purchasing decisions.