In StockwellvCity & County of San Francisco, No. 12-15070 (9th Cir. Apr. 24, 2014), plaintiffs claimed the police department’s decision to abandon a certain examination as a basis for assignments had a disparate impact on the class, based on age.  Examining the merits, the district court found plaintiffs’ statistical model was inadequate and denied certification.  The Ninth Circuit reversed, and explained that merits issues may be considered at class certification only to the extent they are relevant to determining whether Rule 23 prerequisites have been met.  The issue at certification is whether the common issue is capable of class-wide resolution, not whether it will be resolved in favor of the class.  The district court erred, the Ninth Circuit found, by denying class certification based on its conclusion that the plaintiffs would not prove their case.  Whatever the failings of plaintiffs’ statistical model, those failings affected every member of the class uniformly.  Thus, certification was proper.