When will a judge order a new trial on the grounds of insufficiency of evidence?

Since 'it shall be conclusively presumed that said (new trial) order as to such ground was made only for the reasons specified' (Code Civ.Proc., 657), and the ground of insufficiency of the evidence is unsupported by a proper specification of reasons, we conclude that the order granting a new trial must be reversed. Consequently, the judgment in favor of plaintiffs and against the District will be automatically reinstated. (Mercer v. Perez, Supra, 68 Cal.2d at pp. 118--124, 65 Cal.Rptr. 315, 436 P.2d 315.) As previously pointed out, we are presented with no cross-appeal by the District from such judgment. Its finality, therefore, upon reinstatement will automatically follow.