How is the value of a contribution that forms the basis of a finding of unjust enrichment?

On the issue of valuation of a contribution that forms the basis of a finding of unjust enrichment, McLachlin J. stated the following at para. 29 in Peter: From the point of view of doctrine, "[t]he extent of the interest must be proportionate to the contribution" to the property: Pettkus v. Becker, supra, at p. 852. How is the contribution to the property to be determined? One starts, of necessity, by defining the property. One goes on to determine what portion of that property is attributable to the claimant's efforts. This is the "value survived" approach. For a monetary award, the "value received" approach is appropriate; the value conferred on the property is irrelevant. But where the claim is for an interest in the property one must of necessity, it seems to me, determine what portion of the value of the property claimed is attributable to the claimant's services.