What is the test for a review of a decision by a reviewing court to grant approval for a residential development?

The opinion also states: "The petitioners, in addition to raising the issue as to whether the proposed subdivision was consistent with the district plan, raised issues such as to whether the proposed subdivision would cause excess traffic and whether an environmental impact report was required. Failure by the council (and planning commission) to make findings to support its ultimate decision resulted in inability of a reviewing court to bridge the analytic gap between the evidence and the ultimate decision of the council (and planning commission). (See Topanga Assn. For A Scenic Community v. County of Los Angeles, 11 Cal.3d 506 (113 Cal.Rptr. 836, 522 P.2d 12), supra.)" (Id., at pp. 837-838, 118 Cal.Rptr. at pp. 863-864.)