What is the effect of deferring the entry of a final judgment in a class action?

There are, however, countervailing factors tending to support the appellants' position. An appellate court, in reviewing a final decision on substantive issues, would be reluctant to upset the class status after the expenditure of the time and effort the parties and the district court expended in reaching that final decision. Thus, deferring review until after the entry of a final judgment may well prevent any effective review at all of the class action designation. Cf. City of New York v. International Pipe and Ceramic Corp., 410 F.2d 295, 301 (2 Cir. 1969) (Hays, J., dissenting).