What is the test for variation of custody?

The leading case on variation of custody is Gordon v. Goertz, 1996 CanLII 191 (SCC), [1996] 2 S.C.R. 27 (S.C.C.). In that case, the court considered the principles underlying a request to move a child from Canada to Australia. The court held that the threshold question was whether there had been a material change in the child’s circumstances, such that the child’s needs were altered or the ability of the parents to meet the child’s needs had changed in a fundamental way that materially affected the child. In addition, the court held that the change must not have been foreseen or reasonably contemplated by the judge who made the initial order: paras. 12 – 13.