In a decision issued last week, Vallario v. Vandehey, the Tenth Circuit provided some guidance for when it will exercise its discretion to take interlocutory appeals from class certification decisions. The court concluded that interlocutory review of a district court's class certification order is generally appropriate in three situations: (1) when a "questionable" class certification order is likely to force either party to resolve the case based on grounds independent of the the merits; (2) when granting review may facilitate the development of the law; and (3) when the class certification order is "manifestly erroneous." In adopting this approach, the court noted that it followed reasoning articulated by the D.C. Circuit and the Ninth Circuit. With respect to the first situation, I'm not entirely sure how the court expects the "questionable" modifier to be applied. The court's discussion in this regard provides examples of when a certification order effectively ends the litigation because of cost considerations, but appears to provide no guidance for assessing whether a particular class certification order is "questionable."