Whether a class action is superior to individual litigation depends on the case and is determined by the judge's ruling on a motion for class certification. The Advisory Committee Note to Rule 23, for example, states that mass torts are ordinarily "not appropriate" for class treatment. Class treatment may not improve the efficiency of a mass tort because the claims frequently involve individualized issues of law and fact that will have to be re-tried on an individual basis. See "Castano v. Am. Tobacco Co.", 84 F.3d 734 (5th Cir. 1996) (rejecting nationwide class action against tobacco companies). Mass torts also involve high individual damage awards; thus, the absence of class treatment will not impede the ability of individual claimants to seek justice. Other cases, however, may be more conducive to class treatment.